9k vs 18k gold - what is the difference?

Often customers ask the question, what is the difference between 9k and 18k gold? What are the benefits of 18k gold compared to 9k? There's generally a misconception that 9k is more durable, but this is not always the case. Here we will quickly run through the pros and cons of each alloy.

What Are Karats?

Karats, or carats, refer to the pure gold content in gold alloys, and is a measurement of the ratio of gold to other metals in the alloy. Other metals in alloys can include copper, silver and palladium, with small amounts of zinc and iridium.

Gold is a rather soft metal, which is why it's alloyed with other metals to make it harder. However, in normal life applications, 18k gold is perfectly durable due to other metals present in the alloy.

9k vs 18k gold

Lower karat gold, such as 9k, is not tarnish-resistant but can be easily polished with a jewellery polishing cloth and look like new again.

Obviously, the higher the pure gold content, the higher the cost - the price difference between 9k and 18k pieces is usually around 60%. Generally, we recommend using 18k gold for important pieces such as engagement or wedding rings, or special jewellery set with precious gems.

9k gold is composed of 37.5% pure gold hence the gold mark 375 then alloyed with other metals to produce the desired colour. As there is a smaller gold component and a greater component of other alloys, the metal is less durable than 18ct gold. It will tarnish and corrode more easily, especially when exposed to the wearer's skin acids over time. However, because of the lowergold content, 9k gold is a lot more affordable. It's perfect for more casual jewellery pieces and dress rings with large semi-precious gem stones or earrings that have less contact with the wearer's skin.

18k gold is composed of 75% pure gold and is stamped 750. Because pure gold has more tenacity and flexibility than the other metals it is mixed with, and as it's the dominant component, this alloy is more durable and is unlikely to corrode and tarnish with normal wear. 18k gold is perfect for wedding and engagement rings and jewellery pieces that are to be worn every day. It's our preferred metal for precious gems such as diamonds, spinels, tourmalines, opals and sapphires. It's the more expensive choice, however highly worthwhile for fine jewellery pieces.

In Australia, we typically make jewellery in 9k, 14k or 18k gold. 22k and 24k yellow gold is also used in jewellery, with 24k being 100% pure gold.

Precious emeralds in bespoke jewellery

Precious emeralds have been used in bespoke jewellery for centuries. Emerald is part of “top 3” coloured gemstone suite, along with ruby and sapphire. These highly coveted gems are prized for their beauty, exceptional colour and fascinating historical provenance.

Emerald, Be₃Al₂(SiO₃)₆, is the most precious green coloured gemstone and a member of the beryl gem family, whose members also include aquamarine, morganite, heliodor and goshenite. Trace amounts of chromium and vanadium give emerald its beautiful green colour. Emeralds have been a firm favourite for exquisite bespoke jewellery pieces worn by royalty and stars throughout history.

Emeralds have for centuries been strongly associated with power, beauty and fame, and were the preferred gemstone of many of history’s most beautiful and powerful women. Cleopatra was famous for her love of the verdant gems. The Egyptians were perhaps the first civilisation to mine emeralds in Upper Egypt near the Red Sea, as far back as 3500 BC. With the discovery of the Colombian deposits by the Conquistadors during the 1500s (the indigenous Indians had been mining the Muzo emeralds as early as 500 AD) the superb quality gems became the rage with European courts. The infamous “Isabella Emerald” – a 964 carat emerald crystal – was in the end presented to the future wife of Hernan Cortez in exchange for a large dowry which funded his future voyages. Queen Isabella of Spain was furious that it wasn’t presented to her and always coveted the mystical gem.

Screen goddess Elizabeth Taylor had a tremendous passion for exotic gems and Richard Burton presented her with the iconic Bvlgari emerald and diamond necklace as a wedding gift in 1964 (as well as other treasures during the 1960s and 70s). Contemporary actress Julianne Moore had the honour to be the first person to wear the necklace after Ms Taylor in 2013. Superstar Angelina Jolie made headlines wearing large emerald earrings to the Oscars in 2009.

EMERALD COLOUR

Emeralds of medium to dark tone with strong saturation and bright, vivid green colour are the most valuable. Green is the primary hue in emeralds, with yellow and blue the usual secondary hues.

DURABILITY

Emerald is reasonably hard and measures 7.5 on the Mohs hardness scale. As most material is highly included, emerald is a brittle stone and care must be taken when wearing emerald jewellery, especially in ring settings. Emeralds can’t withstand the vibrations of ultrasonic jewellery cleaners so should be gently cleaned in warm water with a dash of mild liquid detergent, with a soft brush to eliminate scratching the setting.

VALUE

Emeralds are 20 times rarer than diamonds and their per carat price can be four times as great. Emeralds with no visible inclusions are valued more than the more included material. Internal inclusions in emeralds are called “jardin,” French for "garden" due to their mossy appearance.

Emerald has lower density than other gemstones and an emerald weighing 1 carat is larger in physical size than a 1 carat diamond.

SOURCES

The first known emerald mines were in Egypt, believed to be worked as early as 3500 BC. Traditionally Colombian emeralds are the most prized on the contemporary market, and Colombia is by far the largest producer, with three main mining areas being Muzo, Coscuez, and Chivor. Due to a natural phenomenon, the gems are produced hydrothermally due to huge surges in heat and pressure when two different rock types come together. They are coloured by chromium and vanadium and have the most gorgeous rich silky green colour.

In the 1920s a significant emerald deposit was discovered in Zambia, however mining didn’t become established until the 1970s. Many of the major jewellery houses now use the Zambian material. Generally the African material has more of a blue undertone (due to lower vanadium content) and the stones are generally less included than their South American cousins. Zambia is now the world's second largest producer of emeralds.

Even Australia is blessed with our own emerald deposit in Torrington, NSW. These very rare gems are unique, often with green and clear banding and truly are collector’s items. The deposit has long been exhausted which makes these stones even more covetable.

Emeralds are also found in Afghanistan, Austria, Brazil, Cambodia, Canada, China, Ethiopia, India, Italy, Kazakhstan, France, Bulgaria, South Africa, United States, Tanzania and Russia, among others.

TREATMENTS

The majority of emeralds on the market today is treated by a process called oiling to improve clarity and stability. This is a widely adopted and accepted practice. Oils with a similar refractive index to the emerald are used, and are applied post cutting in a vacuum chamber under mild heat.

SYNTHETICS

Synthetic emeralds have been produced since the 1960s, using both the hydrothermal and flux-growth techniques. The chemical and gemological composition of synthetic emeralds is identical to natural emeralds, and they are widely used in jewellery. While synthetic emeralds are difficult and expensive to produce, they are nowhere near as valuable as natural, mined emeralds.

EMERALD SPECIFICATIONS

Hardness: 7.5-8 Mohs

Specific Gravity: Average 2.76

Refractive Index: N_ω = 1.564–1.595, N_ε = 1.568–1.602

Crystal Form: Hexagonal (6/m 2/m 2/m)

Treatments: Oil

Durability: Brittle, should be worn with care

Image: Bespoke Emerald, Sapphire And Diamond Ring By Lizunova Fine Jewels

Sapphire

Sapphire is a precious gemstone and part of the most important gem family - corundum, which also includes ruby. Both sapphire and ruby have been used in important jewellery, such as imperial crowns, for centuries, and have consistently risen in value and popularity, due to their rarity, beauty, durability and versatility. Sapphire and ruby have the same chemical composition and structure, with presence of certain metals determining their colour. Corundum is also known for its high density, unusual for a transparent mineral.

SAPPHIRE COLOURS

Sapphire is the most precious blue gemstone, and blue is sapphire's most well known colour. But sapphires naturally occur in a rainbow of colours beside various shades of blue: teal, black, white, grey, orange, pink, green, purple, yellow and the rare and extremely valuable Padparadscha (pinkish orange).

Bi-colour or parti sapphires (stones with two colours in the same crystal, eg yellow and blue) occur in Australia as well as Africa (Madagascar, Tanzania and Nigeria).

All sapphires are made of the same elements, aluminium oxide (α-Al₂O₃)but the trace elements present in the growing process, such as such as iron, titanium, chromium, vanadium, nickel and magnesium, give each stone its unique colours.

DURABILITY

Corundum family is the hardest, most durable natural gemstone after diamond and measures 9 on the Mohs hardness scale, making it a popular choice for jewellery worn every day, such as engagement rings. Despite their durability, they should be protected like any other precious stone, and sapphire jewellery should be removed before engaging in heavy work, such as gardening or construction, or work that would expose them to harsh chemicals.

VALUE

Sapphires have for centuries been associated with wealth and royalty. Sapphires, especially bigger stones, are valuable gemstones, but those of high colour saturation and particular shades of blue - royal blue and cornflower blue), as well as pinkish orange (Padparadscha) are particularly prized. Blue sapphires are valued for the purity of the blue hue, without secondary hues of purple or green. Blue sapphires of vivid saturation and pure blue hue command the highest prices. Vivid pink sapphires, their colour and saturation determined by the quantity of chromium, are also highly prized. Red corundum is called ruby, less saturated stones are classified as pink sapphires.

SOURCES

Sri Lanka produces many beautiful sapphires of gem quality. Blue sapphires from Kashmir and Sri Lanka are among the most valuable. Other sources of sapphire include Africa (Tanzania, Nigeria, Madagascar, Kenya, Malawi), Brazil, Myanmar (Burma), Thailand, Vietnam and United States (Montana). Many of the unique parti and green sapphires hail from Australia (Queensland and New South Wales).

TREATMENTS

Heating sapphires is a common treatment that lightens or intensifies colour, improves uniformity and enhances clarity. A sapphire is gently heated in a kiln to remove or dissolve any silky rutile inclusions back into the matrix of the stone. Heating does not damage the sapphire and is a lasting treatment that does not wear off with time.

SYNTHETICS

Sapphire and ruby have been synthesised since the beginning of the 20th century. Synthetic sapphire is mostly used in many industrial applications, such as scratch resistant glass, semiconducting circuits and lasers. Synthetic sapphires can be recognised under magnification by their curved growth lines following the top surface of the rough crystal. Natural corundum crystals have angular growth lines expanding from a single point and following the planar crystal faces.

SAPPHIRE SPECIFICATIONS

Hardness: 9 Mohs

Specific Gravity: 3.95-4.03 (sapphire)

Refractive Index: 1.760-1.774

Crystal Form: Trigonal. Sapphire crystals occur as barrel-shaped, double-pointed hexagonal pyramids and tabloid shapes. Corundum is found in igneous and metamorphic rocks and also in alluvial deposits.

Treatments: Heating

Special Care: None

Durability: Very good

Image: Parti Sapphire Engagement Ring By Lizunova Fine Jewels

Salt and pepper diamonds

Salt and pepper diamonds have become a popular choice in engagement rings due to their uniqueness and are natural diamonds that are heavily included. Each one has distinctive markings, some resembling a pattern of stars in the night sky – these are called galaxy diamonds. These black markings are carbon spots, pieces of the diamond that never crystallised properly. Salt and pepper diamond engagement rings vary greatly in design as well as the shape of the centre stone, and can be anything from classic to asymmetric and non-traditional.

CUT

They are available in a number of shapes from the more traditional round, oval, cushion, pear and emerald cut, to the unusual, such as kite, hexagon, lozenge and freeform. Rose cut stones (ones that have a flat back and a faceted top) don’t provide as much light return or sparkle as the brilliant cut ones (with a traditional crown and a full pavilion), which scintillate similarly to their colourless counterparts and are more highly valued.

COLOUR

Presented in a variety of colours from white, grey, black to yellow, brown, champagne, blush and pink.

DURABILITY

Diamond is the hardest-known mineral, and salt and pepper diamonds are no exception. However, salt and pepper diamonds need to be carefully selected, as much of the material can be poorly cut and contain cracks and chips.

VALUE

Salt and pepper diamonds are technically lower in quality, as dictated by the four Cs (cut, colour, clarity, carat) of diamond evaluation. But if you find their uniqueness attractive, the good news is they are much more affordable than colourless diamonds.

SOURCES OF DIAMONDS

Angola, Australia, Botswana, Namibia, Russia, South Africa, Zaire.

Major cutting centres of diamonds are in Antwerp, Bombay, New York, Tel Aviv.

DIAMOND SPECIFICATION

Hardness: 10 Mohs

Specific Gravity: 3.417-3.55 (diamond)

Refractive Index: 2.417 -2.419

Crystal Form: Cubic. Diamond crystals occur well-shaped as octahedra, cubes, rhombic dodecahedral and macles. Diamond is found in igneous rock formations and alluvial deposits.

Treatments: None

Special Care: None

Durability: Very good

Lab grown diamond engagement rings

Lab grown diamonds have been used for industrial purposes since the 1950s and gradually made their way to the jewellery market. Nowadays, natural and lab grown diamonds coexist, accepted by both consumers and the trade. Lab grown diamond engagement rings have been gaining popularity due to their much lower cost and excellent colour, clarity and cut.

With identical looks, hardness and durability to the natural diamond, lab grown diamonds represent better value for money (costing on average 30-40% less than a natural diamond), with couples being able to afford a bigger, better quality stone to set into their engagement ring.

Lab grown diamond (also referred to as synthetic diamonds, man-made diamonds, laboratory-created diamond, or cultured diamonds) is a gemstone made of the same material as its natural counterpart: pure carbon, crystallised in an isotropic 3D form. Lab grown diamonds are not imitation diamonds, which are made of non-diamond material.

Man has attempted to synthesize diamonds since the late 19^th century, however, the first reproducible synthesis of a diamond took place in 1950s in the Soviet Union, United States and Sweden, via the CVD (chemical vapour deposition) and HPHT (high-pressure high-temperature) methods. These two processes still dominate the production of lab grown diamonds today.

The only chemical difference between lab diamonds and natural diamonds is that
most natural diamonds contain tiny amounts of nitrogen, and lab diamonds do not. Of course there is more to a diamond than just its chemical structure. According to professionals with over 50 years of experience in diamond sales, there is energy that sort of speaks to you and can be felt the moment you hold a natural diamond in your hand. However, both lab grown and mined diamonds look identical, and only sophisticated technology can help tell the difference between a natural diamond and its synthetic counterpart.

CVF DIAMONDS

Chemical Vapor Deposition (CVF) method where the diamond is grown from a
Type IIa natural diamond seed. These diamonds have the same chemical
composition and molecular structure as mined diamonds.

Type IIa is the rarest and purest type of natural diamond crystal that sparkles more
and shines brighter, with the least amount of impurities, especially nitrogen.

Less than 2% of all diamonds ever found in nature are Type IIa. Today, the CVF
method allows to buy a bigger, cleaner and Type IIa diamond for the same spend. Like mined diamonds, laboratory grown CVD Type IIa diamonds, have very few higher grade colours, D, E and F colours are very rare - like in nature, there is very little control over the colour.

HTHP DIAMONDS

High Temperature High Pressure (HTHP) method where the diamond is grown from a metal catalyst. HPHT diamonds are made using one of three manufacturing processes: a belt press, a cubic press, or a split-sphere (BARS) press. With HTHP lab grown diamonds, the colour is controlled, thus higher colours are readily available. Larger HTHP lab grown diamonds can contain a metal catalyst and sometimes even stick to a magnet.

The advent of synthetic gems on the market created major concerns in the diamond trading business, as a result of which special spectroscopic devices and techniques have been developed to distinguish synthetic and natural diamonds.

VALUE OF LAB GROWN DIAMONDS

Lab grown diamonds generally cost 30-40% less than mined diamonds, but look
exactly the same. The price difference is for the most part due to the high costs involved in mining and removing tons of earth to find natural gem-quality diamonds.

LAB GROWN DIAMOND SPECIFICATION

Hardness: 10 Mohs
Specific Gravity: 3.417-3.55 (diamond)
Refractive Index: 2.417-2.419
Crystal Form: Cubic
Special Care: None
Durability: Very good

White diamonds: beyond the 4Cs

MORE THAN JUST A SPARKLING GEM: WHAT YOU DIDN’T KNOW ABOUT DIAMONDS

Beyond the 4Cs of white diamonds is a multitude of fascinating facts. Despite the fact that diamonds are made of carbon, there’s something almost supernatural about them. Just the word ‘diamond’ invokes luxury, desirability and toughness. Yet when we think of the element carbon we are more likely to think of charcoal: soft, black, opaque, earthy, lightweight. In contrast with carbon in its low pressure form as charcoal or graphite, carbon atoms in diamond are fixed together in a strong, three dimensional network. This leads to unique physical properties: diamond is a clear, extremely hard, often colourless mineral with a very high density.

Diamonds sparkle and have internal “fire” because of their very high refractive index. This means light is “caught” inside the crystal and re-reflected off the internal surfaces. Faces and facets made by gem cutters accentuate this property.

Diamond is the hardest known substance, the greatest conductor of heat, has the highest melting point of any substance (4090°C or 7362°F), and the highest refractive index of any natural mineral. Diamond measures 10 on the Mohs hardness scale, and is approximately 4 times harder than Corundum (sapphire and ruby), which is 9 on the Mohs scale.

VIOLENTLY ERUPTED TO THE SURFACE

Diamonds form deep within the earth under extreme heat and pressure.

Although diamonds have been prized as valuable gems for a long time, until the early 1700s virtually all traded diamonds came from river gravels (known as “alluvial deposits”) in India. Then in the early eighteenth century diamonds were discovered in Brazil, and from 1866 onwards were mined in South Africa. It was in this country that diamond’s major, violently erupted, volcanic source rock known as “kimberlite” was identified for the first time.

This recognition fundamentally changed the diamond exploration and mining industry, and quickly led to vastly increased production and to the high demand from the modern jewellery industry. Supply of diamonds to the market has long been tightly controlled by a small number of major producers – examples include De Beers (South Africa-Botswana), Al Rosa (Russia), Rio Tinto (Argyle Mine Australia and Canadian mines) and Lucara Diamond Corporation (Karowe Mine, Botswana), the Diavik kimberlite pipe in northern Canada.

DIAMOND COLOUR

Most diamonds are brown or yellow in colour. The jewellery industry has favoured colourless diamonds or those that have a colour so subtle that it is difficult to notice. Diamonds in vivid natural hues of red, orange, green, blue, pink, purple, violet or yellow form a group of Fancy Colour diamonds. They are extremely rare and valuable.

DURABILITY

Diamond is the hardest-known mineral, measuring 10 on the Mohs hardness scale. However, the hardness of diamond is directional. It is hardest parallel to its octahedral planes and softest parallel to its cubic planes.

THE VALUE OF DIAMONDS

Unlike other mined commodities such as copper, gold, oil or coal, diamond has no spot market. Its value is variable and highly subjective, assessed using the 4Cs system: colour, clarity, cut and carat (5 carat = 1 gram). Per carat, uncut diamond values typically vary from around $US10 to $US3,000. Very large (sometimes very historical) gem-quality diamonds however may command price orders of magnitude beyond this. Until 1950s, there was no agreed-upon standard by which diamonds could be judged. GIA (Gemological Institute of America) created the first, and now globally accepted 4Cs standard for describing diamonds.

THE 4CS

COLOUR

When talking about colour range in white diamonds what we are actually looking for is the absence of colour. A truly colourless diamond is extremely rare and highly prized. Most diamonds possess varying degrees of colour creating differences in value. The highest grade for a diamond with absolutely no colour is D and letter grades are assigned alphabetically all the way down to Z. An ‘icy white’ diamond is typically D, E or F. However, some people like the ‘warmth’ of an I, J or K colour. Within a given budget, you should seek the best balance of clarity, cut and carat to find the perfect diamond for you.

CLARITY

Diamond clarity is symbolic of ‘purity’ – the more flaws, the less valuable the diamond. Flawless, VVS (Very Very Slightly included), VS (Very Slightly included) and SI1 (Slightly Included 1) have the least inclusions or flaws. SI2 (Slightly Included 2) is borderline where inclusionsmay become visible to the naked eye. I (Included) rated diamonds have obvious inclusions or flaws visible to the naked eye.

CUT

Of all the 4Cs, cut has the greatest effect on a diamond’s beauty. Two diamonds of the same size, colour and clarity will look visibly different depending on their cut – one may look brilliant and bright, the other dull and drab. The better quality the cut the more brilliance and beauty the diamond will have.

Diamond cut grading runs from Excellent to Poor, with Excellent cut diamonds possessing correct proportions and an even pattern of bright and dark areas.

A diamond that is cut is too shallow, with an overly large spread for its carat weight will “leak” light through the sides or bottom of the stone, while a well-cut and proportioned diamond will reflect out the light through the crown, resulting in superior brightness, fire and scintillation.

Brightness is the measure of light reflected from a diamond.

Fire refers to the scattering of white light into all the colours of the rainbow. Scintillation is the amount of sparkle that a diamond has, and reflections inside the diamond resulting in a particular pattern of dark and light areas.

CARAT

Diamond carat is the standard used to measure diamond weight. A carat equals 1/5 of a gram. As diamonds increase in size, their cost tends to increase exponentially. Weight does not always enhance the value of a diamond – particularly if it is cut badly. Indeed a good cut can enhance the perceived size of a diamond.

DIAMOND FLUORESCENCE

Diamond fluorescence is the tendency for the stone to glow when it is subjected to ultraviolet rays from sources like the sun and fluorescent lamps. It looks like a bluish, a yellow or orangey hue. Once the ultraviolet light source is removed, the diamond stops fluorescing.

The element that creates this effect is boron and only about 30% of diamonds exhibit some degree of fluorescence. It grades from None, Faint, Medium to Strong and Very Strong.

Generally, the presence of fluorescence is undesirable, however if we compare two diamonds that have the same lower colour grade, the diamond that has blue fluorescence will have a whiter face-up appearance, as the blue hue helps mask a yellowish tint. Yellow fluorescent hue will enhance a yellowish colour of a lower colour grade diamond.

RECOGNISED LABORATORIES AND GRADING ORGANISATIONS WORLDWIDE

CIBJO The World Jewellery Confederation

CSA Jewellery Council of South Africa

DCLA Diamond Certification Laboratory of Australia

DPL Diamant PrufLabor, Germany

EGL European Gemmological Laboratory

GIA Gemological Institute of America

HRD Antwerp World Diamond Centre

IGI International Gemological Institute

LASER INSCRIPTIONS

When done by certification companies, laser inscriptions are taken as validation and proof of the quality of the diamond. Moreover, they help to avoid confusion, determine ownership, as well as deter fraud in the diamond industry.

CLUES ABOUT DIAMOND ORIGINS

Many diamonds contain inclusions of other minerals, which are captured samples from the deep Earth rocks in which the diamond grew. These provide important information for geologists. For example, inclusions of the minerals olivine, pyroxene and garnet tell us their host diamonds grew at depths between about 120 and 300km, in a layer of the Earth known as the sub-continental lithospheric mantle.

This layer is part of the Earth’s continental tectonic plates, and lies below the oldest regions of Earth’s continental crust known as “cratons”. Cratons are up to four billion years old – examples include the Australian Pilbara, the South African Kaapvaal, the Canadian Slave and the Russian Siberian craton.

The Pink Star is said to be the largest internally flawless fancy vivid pink diamond ever graded.

BLUE DIAMONDS DEEP, DEEP DOWN

Although the sub-continental lithospheric mantle is the most common source of diamonds, some come from much deeper layers in the Earth. These are called sub-lithospheric diamonds, and identified by mineral inclusions consistent with being exposed to much higher pressures found at depths of more than 650km.

A recent study looked at a type of rare blue diamond like the Hope Diamond. The researchers consistently detected very high pressure mineral inclusions indicating their diamond hosts grew at depths of at least 660km. These diamonds are blue because of the presence of trace amounts of the element boron.

The question of how boron ended up at great depths in the Earth’s mantle is a fascinating one. Boron is an element that on Earth is highly concentrated in the upper continental crust (less than 20km deep) and in ocean water. Its concentration in deeper mantle rocks is typically extremely low. Boron then must have been re-introduced to the deep layers where the diamonds grew.

This would likely have happened through a process called deep subduction, where the boundary of an oceanic tectonic plate (about 100km thick) fails, and the plate then collapses into the deep earth’s mantle. This moves boron and other materials from the shallow layers of the Earth down into depths of over 700 km.

Kimberlite eruptions then bring the diamonds up towards the surface.

Subduction of oceanic lithosphere with boron (B) captured from the oceans and delivered by the subducting oceanic slab to lower mantle depths in excess of 660km. Here the boron is supplied to the growing ultra-high pressure sub-lithospheric diamonds.

A WINDOW INTO DEEP EARTH

In addition to the boron example above, evidence from other diamond mine sites also supports the idea that Earth elements move from relatively shallow to deeper into the Earth through the process of subduction.

This has been detected by tracking different forms of carbon in diamonds from the South African Cullinan mine, and on mineral inclusions in South Australian diamonds.

Deep parts of the Earth still have a physical connection with layers closer to the surface. So yes diamonds are valuable due to being beautiful, hardy and relatively rare – but they also provide a fantastic window into the structure and the history of our Earth.

DIAMOND SOURCES

Angola, Australia, Botswana, Namibia, Russia, South Africa, Zaire. Major cutting centres of diamonds are in Antwerp, Bombay, New York, Tel Aviv.

SYNTHETICS

Lab-grown or synthetic diamonds are a complete copy of a natural diamond that contain the same crystal lattice structure and chemical formula as a natural diamond.

To form a diamond crystal, the element carbon is placed under high pressure and the temperature of the surface of the Sun. Another way to form a synthetic diamond would be through a chemical vapour deposition where a small seed of a diamond crystal is grown layer by layer in a chamber.

Identification of a natural diamond from a synthetic diamond requires specialised equipment. The nature of inclusions in a natural diamond differs from the types of inclusions found in a synthetic diamond. Not all inclusions are easily visible through the naked eye or by using a loupe.

Lab grown diamonds are inscribed with letters “LG” at the base of the stone.

IMITATIONS

Cubic Zirconia, Moissanite, Swarovski Crystal.

SPECIFICATIONS

Hardness: 10 Mohs

Specific Gravity: 3.417-3.55

Refractive Index: 2.417 -2.419

Crystal Form: Cubic. Diamond crystals occur well shaped as octahedra, cubes, rhombic dodecahedral and macles. Diamond is found in igneous rock formations and alluvial deposits.

Treatments: Annealing, Irradiation, High Pressure, High Temperature (HPHT), laser drilling, fracture filling, coating.

Special Care: None

Durability: Very good

Image and ring: lizunova.com

Opal

OPAL TYPES AND COLOURS

There are two main types of opal – precious and common. Precious opal displays iridescence, or play of colour, due to the diffraction of light off the tiny, closely packed silica spheres in the atomic lattice of the gem. Common opal does not possess iridescence due to its silica spheres being random in shape, size and arrangement.

Opal forms in sedimentary rocks or where low temperature solutions bearing silica can percolate through rocks becoming rich in dissolved silicates. Depending on the conditions in which it formed, opal may be transparent, translucent, or opaque and the background colour may be white, black, or nearly any colour of the visual spectrum. Black opal is considered to be the rarest, whereas white, grey and green are the most common.

Precious opal is one of the rarest gems on our planet. Australia is blessed with 90% of the finest precious opal including the famous black opal from Lightning Ridge in NSW. Precious black opal has a black body colour and can sometimes display all the spectral colours when viewed from different positions. Vivid greens and blues are the most common colours, while flashes of red are the rarest. Some precious opals can display distinct patterns such as “Harlequin”, with close set broad patches of colour resembling a mosaic with angular play of colour, and “Chinese Writing”, resembling Asian script, usually in gold and green.

Precious crystal opal from Andamooka, South Australia. Image: Lizunova Fine Jewels.

Opals are commonly cut as cabochons with freeform shapes. This is accepted practice and a result of the cutter wanting to maximise the opal and the colour play found in the rough material. The play of colour and shapes make each opal unique.

Precious black opal from Lightning Ridge (NSW, Australia) set in a gold ring with Ceylon sapphires. Ring and image: Lizunova Fine Jewels.

SOURCES OF OPAL

Precious black opal: Australia (Lightning Ridge, NSW), precious white opal: Australia (Coober Pedy, Andamooka, SA). Opals are also found in Mexico, Brazil, US (Nevada and Idaho), Ethiopia, Honduras, Indonesia, Japan, Peru and Russia.

PRICING OPALS

Opals are all about colour, so the better and more even the colour, the higher the value of the opal. A good stone should have colour spread across the entire surface, with no blank patches.

OPAL CARE

Opals are more delicate than some other gems, e.g. diamonds or sapphires, but well worth the extra care. Solid opal should be cleaned gently with mild detergent in lukewarm water and a soft toothbrush or cloth. Avoid bleach, chemicals, pool chlorine and harsh detergents. Opal is heat sensitive and should never be cleaned in ultrasonic cleaners. As with any other precious gem, avoid wearing opal jewellery where it will get rough treatment, such as gym or gardening. Best to remove opal jewellery before showering and applying creams and perfumes to protect your gem.

SPECIFICATIONS

Hardness: 5.5-6.5 Mohs
Specific Gravity: 1.96-2. 5.
Refractive Index: 1.37-1.47
Cleavage: None
Dispersion: Very low

Sources: gemsociety.org, lizunova.com, The Jeweller’s Directory of Gemstones, Judith Crowe

Parti Sapphires

A gem of choice for engagement rings, sapphire has been enjoying great popularity with couples here in Australia and worldwide due to its beauty, uniqueness and durability. Sapphire is part of the most important gem family, corundum, which also includes ruby. Both sapphire and ruby have consistently risen in value and popularity, due to their beauty, durability and versatility.

SAPPHIRE COLOURS

Sapphires naturally occur in a rainbow of colours: blue, teal, black, white (colourless), grey, orange, pink, green, purple and yellow.

The colour in Australian green sapphire is typically made up of a mixture of yellow and blue coloured banding within the crystal mixing to produce the green colour. When some of these yellow and blue banded sapphire crystals are cut suitably, stones know as ‘parti’ (short for partition) can be created.

Bi-colour or parti sapphires occur in Australia as well as Africa (Madagascar, Tanzania and Nigeria).

The same elements make up parti sapphire as other corundum (Al₂0₃) but the trace elements present in the growing process give each stone its unique colours. Presence of iron gives parti sapphire its yellow colour, and blue comes from a mix of titanium and iron.

Australian sapphires are from alkali-basalt related deposits and are very rich in iron content. Due to varying concentrations of transition elements (e.g. iron and titanium) in the chemical make-up of the parent fluids (sapphire is essentially aluminium oxide), different colours result. The parti sapphires are so special as each stone has a unique combination of zoning and banding. The colour zoning seen in parti sapphires relates to the growth layers of a crystal, and appears as a series of concentric hexagons parallel to the prismatic crystal faces.

DURABILITY OF PARTI SAPPHIRES

Corundum family, which parti sapphire is a member of, is the hardest, most durable gemstone type after diamond and measures 9 on the Mohs hardness scale, making it a popular choice for jewellery worn every day, such as engagement rings. Despite their durability, we should protect them like any other precious stone, and remove sapphire jewellery before engaging in heavy work, such as gardening or construction, or work that would expose your sapphire to harsh chemicals.

PARTI SAPPHIRE VALUE

The rarity of parti sapphires makes them valuable, especially bigger stones, and stones with brighter colours. Compared to Ceylon blue or padparadscha sapphire though, parti sapphire is exceptionally good value and its price keeps increasing.

Blue green peacock parti sapphire, Sydney jeweller Lizunova Fine Jewels — Blue green peacock parti sapphire in a cushion cut, Sydney jeweller Lizunova Fine Jewels

This remarkable 5.5ct cushion cut parti sapphire displays shades of green, teal and blue. Parti sapphires of this size and colour are very rare. Image: Lizunova Fine Jewels

SOURCES OF PARTI SAPPHIRE

While sapphires are most commonly sourced from Africa (Tanzania, Nigeria, Madagascar, Kenya, Malawi), Brazil, Myanmar (Burma), Pakistan (Kashmir), Sri Lanka, Thailand and United States (Montana), many of the unique parti and green sapphires hail from Australia (Queensland and New South Wales).

Australia produced a large quantity of sapphires in the 1970s. Today, Australian sapphire mining is much smaller in scale, and, most commonly, it is individual miners working on their claim. The cost and complications of sapphire mining have ensured good quality Australian sapphires are much more scarce.

Bespoke-emerald-cut-sapphire-diamond-French-pave-engagement-ring-platinum-Lizunova-Fine-Jewels-Sydney-jeweller-6 — A unique Australian parti teal sapphire is set into an Art Deco inspired bespoke engagement ring in platinum and yellow gold, with natural diamonds, by a0 Sydney jeweller Lizunova Fine Jewels, Sydney Australia

This emerald radiant cut Australian parti sapphire, set into a bespoke engagement ring, displays the classic yellow and blue colours, mixing into green tones at certain angles. Image: Lizunova Fine Jewels

TREATMENTS

Heating sapphires is a common treatment that lightens or intensifies colour, improves uniformity and enhances clarity. Gentle heating in a kiln removes or dissolves any silky rutile inclusions in a sapphire back into the matrix of the stone. Heating does not damage the sapphire and is a lasting treatment that does not wear off with time.

SYNTHETICS

Parti sapphire is the only stone that labs can’t synthesise, due to the patchy colour pattern.

SAPPHIRE SPECIFICATIONS

Hardness: 9 Mohs

Specific Gravity: 3.95-4.03 (sapphire)

Refractive Index: 1.760-1.774

Treatments: Heating

Special Care: None

Durability: Very good

Image: Lizunova Fine Jewels

Sources: The Jeweller’s Directory of Gemstones, Judith Crowe; OAGems.com

Parti sapphire | Parti sapphire engagement rings

How do I pick the right jeweller for my engagement ring?

FIVE QUESTIONS TO ASK A JEWELLER

In Sydney, where Lizunova Fine Jewels is based, there are hundreds of jewellers to choose from, which can be overwhelming. How do you know which jeweller to pick?

Buying or commissioning an engagement or wedding ring that symbolises your love and commitment is a big decision. For many people, it’s the biggest sum they will spend on a single piece of jewellery in their lifetime. Ultimately, you want to trust the jeweller who is making your ring. It’s a good idea to not only see but also touch and hold the rings they have previously made – jewellery can look amazing in carefully photographed and retouched images. If you are buying online, I would recommend requesting videos of a ring or a gemstone shot in natural daylight. If you are able to visit the jeweller in person, it's a good idea to look closely at the quality of the rings: the neatness and symmetry of settings and quality of metal and craftsmanship.

Some of the things to look out for, and questions to ask, are:

Is enough metal used in the ring shank and gem setting to last 30 or more years? Thin bands might be on trend right now but will not wear well over time – metal thins out with wear, especially at the base of the ring shank. Dainty bands that don't have enough metal will bend and warp with wear, and any diamonds or gemstones set into them will likely fall out as settings become compromised when a ring gets bent out of shape.
Are the stone settings appropriate for the gems that have been set into them, considering the wear they will get as an engagement or wedding ring? Softer stones need to be set in protective settings, otherwise if worn daily, they will chip and scratch after a few years.
Where is the jewellery made and by whom? Is it ethically crafted by a local jeweller who is paid well for his or her work?
Are the diamonds certified and conflict free?
Are the gemstones natural or man-made (synthetic/lab grown)? Is this reflected in the price?

It’s always a good idea to look at 2-3 jewellers, ask questions, and hold and closely look at a variety of rings to start getting a better understanding of what quality looks and feels like.

WHAT ABOUT GOING DIRECT TO A MANUFACTURING JEWELLER?

If you go direct to a manufacturing jeweller, you’re relying on their taste, the way they’ve always done things and their ability to understand and translate your ideas to a finished piece. They have a different approach and motivation to those of a jewellery designer, and while it may save you some money going direct to a manufacturing jeweller, I would recommend finding a great jewellery designer, whose style and work you love. A good jewellery designer would have an in-depth understanding of many factors involved in creating the perfect ring, not the least of which is how to take the design brief from you in such a way that you end up with the ring you love forever.

WHAT ARE THE LATEST ENGAGEMENT AND WEDDING RING TRENDS AND IS IT A GOOD IDEA TO BUY ON TREND?

Trends come and go. You’re going to have this ring for the rest of your life, so I think it’s a good idea to steer away from fashion and choose a design that’s stylish, well thought-out and timeless.

IF I GO WITH A BESPOKE RING, HOW DO I ENSURE I LIKE THE END RESULT?

The advantages of having a bespoke ring designed and made especially for you is that, if you pick the right designer, you will have a beautiful ring that’s unique to you and expresses your personality and your love story. To ensure you’re getting exactly what you envisage, you need to be given very clear and precise, to-scale design sketches that show the ring from three angles – top view, and two side views. You also need to see and hold the stone that is going to be set into your ring and see what it looks like on your skin.

Modern technology allows us to create 3D colour drawings as well as a to-scale 3D printed wax model of your ring you can try on – so there are no surprises when you receive your finished ring.

IS BUYING ONLINE A GOOD WAY TO SAVE MONEY? ARE DIAMOND WHOLESALERS AND JEWELLERS WITHOUT A RETAIL SHOP CHEAPER?

Jewellery is an intensely personal purchase. I believe it’s about connecting with the piece or falling in love with a stone. While it's fine to buy online from a reputable jeweller, if you have a chance to try on a ring in person, it would be a good investment of time to do so. A good jeweller will accept returns of ready made items bought online, if you are not 100% happy with your purchase. You could also request to see videos of loose gemstones if commissioning a bespoke ring, or a ready made ring worn on a hand and shot in natural daylight. It's important to see a ring worn on a hand, or a stone placed in hand, to give you a better understanding of scale.

A real diamond wholesaler doesn't sell to the general public, and sells only to trade - jewellers and jewellery designers. The so-called diamond wholesalers who sell direct to public are actually retailers. You may pay less but end up with a ring that looks like everyone else's, made without attention to quality or detail.

There are many talented independent jewellers, I believe there’s a right one out there for everyone. Someone you are comfortable with creating your most important piece of jewellery – connection and trust are vital ingredients in a successful relationship between a couple and a jeweller.

We would be happy to talk to you about pros and cons of different gemstones, diamond selection or engagement ring design in person. Drop us a line or call 02 9221 1900 to book a bespoke engagement ring design appointment.

Rhapsody in teal

LOVE AT FIRST SIGHT

“The sense of excitement was almost overwhelming. I just had to hold the mysterious gem, sparkling blue-green in the gem dealer’s hand. It was cool to touch, its oval form as big as a small egg. My nervous fingers held it gingerly while I admired its magnificent sparkle and flashes of colour,” Lizunova Fine Jewels founder, jewellery designer Maria Lizunova recalls. “I fell in love with it almost instantly.”

What could it possibly be? At 109 carats, it was way too big to be an indicolite tourmaline, which are as rare as hen’s teeth in sizes above 1 carat. Matthew, Lizunova’s trusted Sydney gem dealer, finally broke the suspense, “It’s a London topaz, but this colour – it’s a miracle, in all my years of travelling the world and scouring gem fairs, I’ve never seen anything like it.”

A RARE GEM

Natural blue topaz can vary in colour from very pale to inky blue, called London Blue, the most valuable of this spectrum. Topaz also naturally occurs in white and amber colours, the latter, Imperial topaz, is highly prized. Blue topaz never crosses into the green spectrum, and this teal-coloured wonder is a true freak, or gift, of nature.

A cherished possession in Matthew’s mother’s personal collection, it was bought over 20 years ago on a whim – she simply could not resist its highly unusual colour. This enigmatic gem would emerge from time to time to be shown off at gem fairs and trade shows as a showpiece, on the condition it would not be sold. Finally, after years of pleading by her son, she agreed to part with it on one condition, that it would be sold to a jeweller who would set the gem into a design worthy of it.

A MASTER GEM CUTTER STEPS IN

Lizunova decided to change the gem from its original cut, a commercial oval with a typical diamond checkerboard, to something much more contemporary and crisp. Cue Doug Menadue, a renowned Sydney gem cutter - a true gem connoisseur and a master of his craft. He was beyond excited at the opportunity to transform this rare gem.

“I was as thrilled about the opportunity to work with Doug as I was about buying the stone. I have admired Doug’s work for years, and all the gems he cuts bear his unmistakable signature – they’re crisp, contemporary and very beautiful,” says Lizunova.

For Menadue gems and gem cutting are a true passion. Taking a leap to pursue his passion for gemmology and stone cutting, Menadue ended a 20-year career in IT to explore and hone his knowledge in the gem field. His craftsmanship is second to none and every gem he cuts often surpasses expectations, highlighting the beauty of each gem he touches. After much deliberation, Menadue designed a cut especially for this remarkable gem, to optimize light and accentuate the vibrant colour. The new, crisp rectangular octagonal cut, named Rhapsody Lizunova Variation, brings out the best of this magnificent gem, with strong flashes of teal throughout its beautiful, 68.6 carat form. The definition of rhapsody is an ecstatic or enthusiastic expression of emotion, and the newly recut gem truly lives up to its name, inspiring awe and emotion in all who see it.

A BESPOKE JEWEL

“We are so excited to hold this beauty in our gem collection,” says Lizunova. “The minute I had it back from Doug, I was sketching ideas for setting it. I would love it to be a cocktail ring, as topaz is 8 on a Mohs hardness scale. Imagine it in platinum or white gold and diamonds! It would take one brave lady to wear such a large cocktail ring though, so I also sketched ideas for a pendant necklace. The bespoke designs respond to the lines of the Rhapsody cut and would make a truly magnificent, one of a kind jewel.”

Lizunova has a true appreciation for design, with a career in graphic design and art direction spanning over 15 years. For her, just like for Menadue, gemstones and jewellery design are a true passion, worth a radical career change later in life. Similarly to Menadue, Lizunova is self taught, with a truly fresh, contemporary approach to jewellery design.

The brand is fiercely loyal to local, ethical craftsmanship, and uses Australian-made gold, silver and platinum in its designs, with hand-picked gemstones, ethically sourced from local, Sydney gem dealers, front and centre.

“We invite you to view Rhapsody in our boutique. It is a true masterpiece, where natural providence meets craftsmanship.”