Category Archives: Jewellery

Fluctuations of the market in the last few years

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As with every market, jewellery prices will inevitably fluctuate, though I can’t say I’ve seen the price of precious stones go down in the last few years. Seen as a commodity by some and as a treasure by others, it’s important to understand the cost of remaking a unique piece of jewellery. It will be dictated by global demand for diamond (or other precious stones), gold, silver, palladium and other alloy metals and stones.

High worldwide demand for palladium – due to its key importance in the development of renewable energy – inevitably increases the cost of gold – based items of jewellery. Because of its softness, gold used in jewellery is mixed with alloys. Alloys are other metals, such as zinc, copper, nickel, iron, cadmium, aluminium, silver, platinum and palladium. This mix then alters its appearance, hardness and melting point. Palladium is a chosen favourite as an alloy metal. At today’s value, the scrap value for palladium is £41/gram compared to £21.50/gram for platinum, which then impacts gold jewellery pieces.

As an example, this 9ct gold gate bracelet with heart locket was estimated £70-£100 by Bonhams in 2005. Today’s estimate would most likely be £200-£300.

Designer pieces with diamonds are affected in a similar manner.

This diamond and gold bracelet by Kutchinsky (above) sold at Bonhams for £1,553 (including premium) in 2005.

A similar item by the same designer (below) sold for £2,550 (including premium) in 2019.

For insurance purpose, the above bracelet would receive a value of £8,000 as at 2022.

Coloured stones have also seen an increase in price.

This emerald and diamond cluster ring is set with an emerald weighing approximately 5.20 carats and approximately 1.15 carats of diamonds. It was previously valued at £42,000 in 2011 for insurance purpose. Eleven years on, it is now valued at £65,000.

One could try to apply generic inflation percentages as a tool to update valuations, however this is incorrect and will often lead to your jewellery being under or overvalued. In the case of the above ring, a formula trying to reflect inflation would be detrimental to the value of the ring.

Valuing jewellery should always be case by case, as some signed vintage pieces will increase over the years, but not at the same rate as precious gemstones for example. The market for an Art Déco Cartier wristwatch (as below), though rare, has a smaller market of potential buyers and sellers. Comparatively to coloured stones, the value for this wristwatch will never exceed a certain plateau. This watch currently retails for £35,000.

A similar wristwatch by Cartier (below) sold at Bonhams in 2017 for £16,250 (including premium) and would have most likely received an insurance value of £23,000.

Diamonds on the other hand continue to escalate at a steady pace.

These diamonds earstuds (above) are 4.01 carats and 4.04 carats respectively. They were valued for insurance purposes at £300,000 in 2012 and are now valued at £360,000.

The same applies to contemporary signed pieces such as the Alhambra collection by Van Cleef & Arpels.

The mother-of-pearl Alhambra necklace by Van Cleef & Arpels was sold for £9,950 less than ten years ago and now retails for £15,800. A steady increase reflecting world demand for durable contemporary and elegant jewellery by a reputable designer.

The jewellery market is not exempt from worldwide affairs and economic changes, but it will always have an added unquantifiable value: emotional value. Jewellery can be seen as an investment, but it still predominantly remains a purchase of pleasure and luxury, whichever gem or metal one chooses and whatever happens in the world.

Hocus pocus… Focus on… Amber

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To kick off this mini series of Halloween gems, amber is the chosen first. What could be more spooky than trapped insect containing deadly bacteria…

Prized for its deep rich and warm orange hue, amber is an organic gem, meaning that it is created from living or once living organism, it is fossilized tree resin dating tens of millions of years. It is composed of carbon, oxygen and hydrogen. Nicknamed “the gold of the North”, it is most commonly found on Northern Europe’s beaches, washed away with the ocean tides. It can also be dug from the ground and deposits have also been found in the Dominican Republic, Myanmar (Burma) and Mexico.

There is a distinction to be made between amber and copal amber. The latter refers to amber which fossilized less than a million years ago. But who’s counting!! It is also fossilized tree resin and is formed in the same manner. One cannot differentiate between the two using a magnifying glass, but rather by using “granny’s old tricks”. Some say that rubbing copal amber on the heel of your hand will emit a smell, others suggest a drop of acetone or even gasoline to determine copal from mature amber: amber is unaffected by acetone whereas copal softens the material. Either way, probably best to avoid doing at home and damaging one’s precious jewel!

Like with all gems, it takes very specific conditions to create amber. It takes a few million years for resin to harden. Once it has hardened it lays under sediment in an oxygen-free environment. It turns to copal amber. It then takes a few more million years to become more stable with the effects of heat and pressure applied to the copal amber to become amber. Research shows that the deposits found in the Baltic and Dominican Republic came from extended immersion under seawater.

Because of its relative softness – rating at 2/2.5 on the Mohs scale (talc powder rates at 1) – it is not commonly cut with facets, but rather polished into beads or free-form pieces.

Jewellery made of amber tend to be big pieces. The reason for it being the lightness of this gem, making it a perfect candidate to wear around one’s neck without feeling weighed down.

The most prized amber pieces are typically transparent, dark reddish hue. However, amber also comes in white and treatments to enhance colour can modify its appearance totally. Heat treatment and dying are commonly used to enhance amber and one distinct mark to look for are sun spangles. Heating amber can cause fracture-like marks: sun spangles.

Amber is a treasured gem because of the secrets they can unveil. The insects, fauna and animals they have sometimes captured tell a tale.

Inclusions play a huge part in the final value of amber but often if the inclusion is perfect, then it probably is too perfect to be real.

It can be extremely difficult to trust authentic amber with inclusions, such as this piece for sale on eBay for $129,000:

And this perfectly preserved scorpion, also on for sale at eBay for £4.90! :

When in doubt and spending a large amount, always ask for a report from a reputable laboratory.

Man-made or real, amber with insect inclusions make the perfect jewellery piece for trick or treating!

Hocus pocus… Focus on… Skull Jewellery

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Skull jewellery and gemstones

Skulls. Usually not what comes to mind when talking about jewellery design and carved gems. However, skull jewels, and especially rings, have had a long tradition of being part of one’s collection.

The appeal may not be so obvious but it is one that continues to be popular throughout times.

Why a skull? It acts as a reminder. That life is not forever and days are counted. That one should live every day to the fullest, carpe diem. And what’s not to love about that message? Embracing one’s life and accepting your fate, not always fighting against the things we cannot control.

In more recent years, Theo Fennell is recognised as one of the top fashion jewellers to use this symbol of life and has used all sorts of gemstones in his creations to amplify his creations.

If rings are not your go to jewellery item this Halloween, then perhaps a pendant necklace by the same designer could be an option.

Halloween calls for creativity, so this year, why not trade in the pumpkin for a carved gem skull? Sure to get your neighbours quivering in their boots and make a bold statement.

There are a multitude of options. In keeping with the orange theme of the pumpkin, a citrine skull could be an option.

Quartz, which citrine is a variety of, has a hardness of 7/7.5 on the Mohs scale and makes it a good candidate to get sharp edges to carve the teeth and a pointy nose.

It can also come other colours such as purple amethyst:

Or even blue:

A wide variety of options is available on the market, including at specialized auctions.

Bonhams sold this lot in Los Angeles in 2017 for $1,187 incl premium. It includes an amethyst obelisk decorated with twenty carved skulls, Height 11in; a sculpture comprising three skulls with a butterfly, carved of boulder opal from Queensland, Australia, length 5 1/2 in; together with a Mexican black obsidian carving of a skull with owl perched, height 6 1/2 in.

But possibly the most “out of this world” carved skull must be a sculpture sold in 2015 at Bonhams in Los Angeles, carved out of meteorite, making it the largest Gibeon meteorite carving in the world.

Gibeon meteorites are iron-based and “originated billions of years ago from unstable planet that existed briefly between Jupiter and Mars.

When the planet broke apart, a section of its core travelled through space for four billion years.” It penetrated the Earth’s atmosphere about 1,000 years ago and landed in Namibia.

This particular 21kgs life-sized carving, nicknamed Yorick, was created from a 280kgs meteorite. It is one of the rarest forms of meteorite.

The choice is vast for Halloween decorations whether for the house or fashionwear. All one needs to do now is pick the right outfit for a night of trick or treating…

Ametrine

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Ametrine is a form of quartz. It combines both the purple amethyst and the yellow citrine all into one stone, making it somewhat of a unique specimen. To add to this uniqueness, commercial ametrine is only found in Bolivia, and more precisely in the mine of Anahi.

What do we mean by commercial? Stones that are of a particular quality that can be cut and set into jewellery.

The mine was named after a legendary princess of the 1600s who married a Spanish conquistador and was given the mine as dowry. The mine located in a very remote area of Bolivia, was lost for centuries. Research shows that the mine was only rediscovered in the mid-50s, only accessible by plane and small boats.

Ametrine displays the same properties as amethystand citrine. Ametrine rates a 7/10 on the Mohs scale. The Mohs scale of mineral hardness was created by Friedrich Mohs in 1822 and determines the scratch resistance of minerals when scratches by another mineral.

The Mohs scale is used to manufacture everyday objects: your mobile phone’s screen glass is made of a material that scratches at level 6, some at level 7. Ametrine therefore has good toughness and is suitable to be set in jewellery, such as this sapphire and ametrine torsade necklace which sold at auction for $408 (pictured below).

It can be noticed that ametrine is most commonly found in jewellery as a rectangular-cut stone. This cut displays the bi-colour property of the gem, exposing both colours at its best, with the clear demarcation between the yellow and the purple. The most prized ametrine will display fine transparency, a good contrast of colours and an equal balance between the two colours. Though it rates rather high on the Mohs scale, its colour can fade if exposed for long periods of time to too much bright light. If ametrine is worn in jewellery, its wearer should be aware of its possibility to scratch and chip if not cared for properly.

How would one care for its ametrine-set jewels? The best and safest way to clean your jewellery is with good old fashion soap and warm water and not exposing it to high heat. It is preferable not to place the gem in an ultrasonic in case the stone or others in the piece of jewellery have been dyed or fracture filled (the machine’s vibrations will remove the modifications).

Because of its extraordinary features, ametrine is often carved into fantasy-cuts.

An ametrine carving of rooster by Gerd Dreher sold at auction for $12,575. Dreher is a German animal figure carver, the fourth generation of Dr eher in this line of activity. He was born in 1943 in Idar- Oberstein, one of the most important gemstone centres in the world with the finest lapidaries and gem cutters.

This gem-set obelisk / jewellery box by Manfred Wild (pictured top right) remained unsold at $200,000- 250,000. Wild aas born in 1944 in Kirshvayler near Idar-Oberstein. He is the eighth representative of the family dynasty that has been engaged in lapidary art since 1630. Manfred Wild is sometimes called “The 21st century Fabergé”.

Ametrine is used in a wide range of carvings for its intriguing features. It is not uncommon to see jewels set with ametrine but it seems to be slightly underappreciated for what it is: an exceptional wonder of nature who combines two stones into one giving it a delightful play with colours.

I is for iolite

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Iolite is the gemstone variety of cordierite, a magnesium, iron, aluminium and cyclosilicate mineral named after the French geologist Pierre Cordier (1777 – 1861) – founder of the French Geological Society.

As with some other blue gemstones, iolite is known for its pleochroic properties giving it that extra sparkle. Pleochroism is an optical phenomenon in which a substance has different colours when observed at different angles, especially with polarized light.

Iolite occurs in several areas of Africa, including Kenya and central Tanzania. In fact, when Tanzanite was first discovered, geologists thought it was corderite.

Other iolite source countries include India, Brazil, Norway and a large deposit found in 1994 in Madagascar.

The name iolite comes from the Greek word ios, meaning “violet”. It is said that iolite slices were used by Viking navigators to locate the sun on cloudy days, used as some form of compass.

The gem rates at 7 to 7.5/10 on the Mohs hardness scale. The Mohs scale of mineral hardness was created by Friedrich Mohs in 1822 and determines the scratch resistance of minerals when scratches by another mineral.

The Mohs scale is used to manufacture everyday objects: your mobile phone’s screen glass is made of a material that scratches at level 6, some at level 7.

Even though iolite scores rather high on the Mohs scale, it has strong cleavage in one direction, giving it only a fair toughness. Cleavage, caused by weak atomic bonds, is the weakest plane in a gemstone where the gemstone can split.

For this reason, jewellers are a little reluctant to use the gem in jewellery, specially any hard-wearing jewel such as rings for example.

The gem’s most sought after colours are violetish blue to fine blue. But iolite can appear to be greyish, even transparent, or golden and even brown. Depending on where the light hits, differentcolours will show. For this reason, iolite can be confused with colour change sapphires.

Vivid violetish iolites over 5 carats are rare and cannot be treated in the same way as corundum (sapphires) can be. Unlike sapphires, iolite’s chemical composition won’t allow it to be heat treated to intensify its colour. The gem would simply melt at such high temperatures.

Iolite is more often than not faceted, bringing out its unique transparency, free of inclusions.

But it also is a popular choice for cabochons.

In some iolites, a phenomenon called cat’s eye can sometimes be observed. This effect comes out at its best when the gem is cut as a cabochon.

The cat’s eye effect is caused by long, parallel, tubular inclusions. It can also be found in other gems such as sapphire and chrysoberyl.

Though iolite is hardly ever treated, making it a very appealing affordable blue-gem alternative, due to its relative hardness and lack of consistent fine quality supply, it is not found in as many workshops as tanzanites for example. However, iolite is also cut as beads and strung to make beautiful colourful
necklaces.

A wonderful twenty-first wedding anniversary gift…

The Imperial State Crown

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If one wants a glimpse of The Imperial State Crown, it is on display in the Jewel House at the Tower of London, as it has been for the last 600 years. But on the 19th September 2022, this most unique and priceless item of jewellery laid on her Majesty The Queen Elizabeth II’s coffin for her final farewell.

Imperial State Crown

During her reign, Queen Elizabeth II would wear it annually for the State Opening of Parliament, sharing in 2018 that “You can’t look down to read the speech, you have to take the speech up, because if you did your neck would break”. The crown weighs 1.06kgs.

Queen Elizabeth wearing the Imperial State Crown

Monarchs wear the Imperial State Crown when departing from the Abbey after the coronation, and for all other occasions requiring crown-wearing thereafter.

Originally made by Rundell and Bridge in 1838 for the coronation of Queen Victoria. It was commissioned for the coronation of the Queen’s father, King George VI in 1937 from Garrard & Co.

The crown is set with historical gems with nearly 3,000 stones – including 2,868 diamonds, 273 pearls, 17 sapphires, 11 emeralds, and five rubies.

The Culinan II, or Second Star of Africa, weighs 317.4 carats, with 66 facets.

Cullinan produced 9 major stones of 1,055.89 carats in total, including the Cullinan II, plus 96 smaller brilliant and some unpolished fragments weighing 19.5 carats. The Cullinan diamond was found in 1905 in South Africa’s Premier Mine at Cullinan, named after Sir Thomas Cullinan, who opened the mine in 1902. It is believed the diamond surfaced 1.18 billion years ago. Originally thought to be some priceless crystal, the mine’s manager did not give another look when the miner found it. He persevered, and it then became the largest diamond to be found.

It was sent to London in a plain box via registered post and presented to King Edward VII. It remained unsold until 1907.

The Transvaal Colony government bought the diamond on 17 October 1907 for £150,000, the equivalent of £18 million. It was presented to the King on his 66th birthday at Sandringham House.

He accepted the gift “for myself and my successors” and ensured that “this great and unique diamond be kept and preserved among the historic jewels which form the heirlooms of the Crown”

The king chose Joseph Asscher & Co. of Amsterdam to cleave and polish the rough stone into brilliant gems of various cuts and sizes.

Cutters here in Amsterdam plan how the stone should be cut. It took 8 ½ months to cleave and cut.

The images above show Joseph Asscher cleaving the Cullinan.

On the first blow, Asscher’s hammer blew off. It was on the second attempt that the diamond shattered into 9 pieces.

Cullinan I is set in the sceptre, which also laid on the Queen’s coffin.

The Black Prince’s ruby, in its prominent place on the crown, is in fact a spinel. It was only in 1783 that spinels were differentiated from rubies. They share many chemical properties, such as aluminium, oxygen, and chromium but spinels also have magnesium.

This “ruby” is said to have been in English royal hands since the 1360s.

It was probably discovered in the Himalayan mountains of central Asia, in the Badakhshan (Balascia) region that was famed for its spinels. It drilled at some point to be worn as a pendant. The hole was later filled with a smaller cabochon ruby edged in gold.

It was supposedly worn by King Henry V at the Battle of Agincourt in 1415 and saved him from an axe blow to the head, struck by the Duke of Alençon. Henry survived, as did the ruby, and the English were victorious.

The Stuart Sapphire is set at the back of the crown and weighs approximately 104 carats.

In Youngblood and Davenport “The Crown Jewels of England”, they describe the stone as follows: “oval in shape, about one and a half inches in length, by one inch in breadth, and is set in a gold brooch. It has one or two blemishes, but is of good colour, and was evidently deemed of high value by the Stuarts. At one end has been drilled a hole, probably to introduce some attachment by which the stone could be worn as a pendant.”

Queen Victoria, was the first monarch to have the sapphire set in her state crown. During Victoria’s reign, the sapphire was set at the front of the crown, just below the Black Prince’s Ruby.

After the discovery of the Cullinan diamond, the sapphire was relocated to the back. There is still some mystery as to whether the Stuart sapphire in The Imperial State Crown has been the same gem since it was first used in royal jewels in 1660 but it certainly has been in the collection for over two centuries.

These priceless gems, the Cullinan II, the Black Prince’s Ruby and the Stuart Sapphire are a reminder of majesty, sovereignty and tradition embodied in the institution. Following tradition, King Charles III will wear the St Edward’s Crown for his coronation, but will put on the Imperial State Crown to leave Westminster Abbey at the end of the ceremony.

God Save the Queen, Long Live the King.

The one that got away…

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I don’t recall the life-changing opportunity that was missed; perhaps that’s just as well. It would be galling to know that one had passed up an opportunity to buy something that went on to make multiple times the purchase price.

I do remember seeing two wonderful pairs of enamel cufflinks being sold very inexpensively at an antiques fair. The seller was insistent that he would only accept cash, and as I didn’t have that sum of money on me I asked him to hold them whilst I went to a cash point. When I returned, having extracted the maximum possible from three bank accounts, he nonchalantly informed me he’d sold them to someone else. Hard money on the spot clearly talks.

I also remember the insurance valuation I did for a couple who had recently downsized. Referring to a previous valuation schedule I queried the whereabouts of an impressive Victorian inkstand by a well-regarded maker. They informed me that they had had to dispose of a great deal in the move and they had sent the inkstand to a local charity shop, believing it to be silver plate and of little consequence. They were stoic about the discovery. No point in crying over spilt ink!

What has got away from me is trends. I wish I could have called the rise and fall of gold prices better. If only I’d known that as cigarette smoking fell from grace, there would be an unexpected rise in the popularity of cigars and cigar related memorabilia. Thirty odd years ago American Marvin R. Shanken launched Cigar Aficionado, and this venture set off perhaps the most unforeseen social craze of the 1990s — the renaissance of cigars and an explosion in the popularity of all cigar-related paraphernalia. This too has now largely fallen away.

One of my career-long passions has been cufflinks. I have supplied literally thousands of pairs of antique and vintage cufflinks to organisations both here and in America. I’ve constantly been told that they would be going out of fashion and that no one would want the bother of double cuffed shirts anymore. However, even as the tie has fallen from grace, the tailored shirt has remained a wardrobe staple and notwithstanding the hiatus of the pandemic cufflink sales are on rise again as workers return to offices. I have just sourced an Art Deco dress set for a well-known film franchise that wanted the genuine article and not a modern copy. I’m really glad that one didn’t get away.

The great thing about our world is that there is always tomorrow. There is endless speculation about where trends are going and what individual pieces might make. It’s one of the things that makes the art world so interesting. We all bring our expertise to bear on determining accurate prices, but the marketplace can be capricious and that’s what makes it exciting. Fashions come and go, and unexpected left-field shifts like the rise of NFTs can cause a significant change in thinking. Being able to foresee these repositioning of market forces would be a really useful superpower.

Eventually, most people are pragmatic about missed opportunities, which sometimes presents a chance to rethink and learn. I have a huge collection of single cufflinks that are partnerless. I shall let you decide if this collection should be viewed as the ones that got away or the ones that were saved. I prefer to think of them in the latter category, however, I’d be overjoyed to find their partners and restore the marriages.

The one that got away…

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Some time ago, I worked at Bonhams, in the jewellery department. Along with the regular monthly sales held in Knightsbridge were pawnbrokers’ auctions. These were comprised of any jewellery items which had not been redeemed by a customer and needed to be sold on the open market to obtain a fair price and hopefully achieve the best price for it.

The excitement and unpredictability of an auction never fades and each sale kept us on our toes. With pawnbroker sales, that unpredictability was tenfold. Because a pawnbroker client had until the very last moment to redeem his/her item, this meant that items could be withdrawn from an auction at any point prior to the item’s lot number being called out by the auctioneer.

In this case, the one that got away was a magnificent Burmese sapphire ring up for sale in the pawnbroker’s auction. Because pawnbroker auctions are so volatile, there are no catalogues and therefore no image, so I will do my best to convey this ring’s uniqueness.

The sapphire was Burmese. That in itself, is usually indication enough to express the velvety blue hue that sapphires from this part of the world have. Burmese, or Kashmir, sapphires are the most coveted sapphires, considered to have the deepest, intense and rich blue hue. Also known as “Royal Blue”.

Sapphires belong to the same family as rubies, they are corundum. Any coloured corundum, other than red, is called a sapphire. Sapphires differ from rubies in that they have iron as part of their crystal lattice.

Both sapphires and rubies from Burma make for the most exquisite gems. The value in a Burmese sapphire lies in the depth of colour and its dispersion. This is due to minute crystalline inclusions in the stone. Inclusions are small “imperfections” captured in a stone during its formation.

They are like fingerprints, unique to every gem. Below are a few examples of inclusions which are found in sapphires. These help identify where a gem formed, where it was mined and if the gem is natural (as opposed to synthetic, or man-made) and if it has had any treatment to enhance the colour or make inclusions less visible.

Mogok Sapphires

The sapphire in the ring that was up for auction had beautiful silk crystal inclusions and certainly had that “Royal Blue” hue about it. The most famous “Royal Blue” sapphire is probably the one set in Kate Middleton’s sapphire and diamond engagement ring, which belonged to her mother-in-law, the late Princess Diana.

The sapphire weighs 12 carats and is set within a surround of brilliant-cut diamonds. When it was made in 1981, the sapphire ring cost £50,000. Because of the provenance and history of the ring, it has become a priceless piece of jewellery, but one could estimate its current price to be around £500,000.

The world’s most expensive sapphire to sell at auction was sold at Sotheby’s Hong Kong on the 7th October 2015. It weighed 27.68 carats of natural Kashmir origin and made $6,702,564, $242,415 per carat.

It is common for these exceptional sapphires to be accompanied by multiple certificates. If one is to buy a gem, whether for pleasure or investment purposes, it is recommended to buy one with a certificate from a reputable laboratory such as SSEF, GIA, Gubelin.

Don’t be fooled by reports sold with sapphires in markets which simply state that the sapphire is a corundum and details its shape and weight. The stone could well have been man-made in a laboratory in which case a report should state “natural” or “synthetic”.

A gem can also be treated to make it more desirable. It is common practise for sapphires to be heat-treated to bring out more colour in the stone. This should also be mentioned in the report, along with any other enhancements.

Whatever the price of the gem, look for clarity from the seller/dealer/jeweller. If there is transparency and one knows what they are paying for then an honest transaction can proceed. If in doubt, walk away.

I was convinced this sapphire ring was a good investment opportunity. And I would have been right! Sapphires, like rubies and emeralds for example, have seen a net increase in value in the recent years. A similar ring to this superb sapphire ring selling for £25,000, would probably exceed £100,000 at auction in the present climate.

Unfortunately, the sapphire ring was to be pulled from auction moments before the sale was to start and this will forever be The One That Got Away…

G for Garnet

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Garnet is one of the oldest known stones to man. It is the first gem mentioned in the Bible, in Hebrew “nophek”. Indeed the Talmud mentions garnet as being Noah’s only source of light in the Ark in the form of a carbuncle. A carbuncle often refers to ancient red garnet and red stones in general. It was one of four stones to be given by God to King Solomon.

Garnets have also been found to adorm Egyptian mummies, set in necklaces and other jewels. The oldest red garnet bead necklace to have been found is believed to be from 5,000 BC.

In ancient Rome, signet rings with carved garnets were used to stamp the wax that secured important documents.

Because the gem comes in such a wide range of colours, they each have a specific name.

The green garnets are also called tsavorite – named after the Tsavo Game Reserve in Kenya where it was first found by British geologist Campbell R. Bridges in 1967 and named by Harry Platt of Tiffany & Company.

My favourite is perhaps the demantoid garnet for the inclusion it sometimes hold: a horsetail. An inclusion is any material trapped within a stone during formation. In the case of a horsetail, a formation of golden feathery inclusions of chrysolite form in curves resembling the tail of a horse.

Rhodolite is a purplish red variety. Red garnets are also called almandine, pyrope, whereas the more orangey type are called spessartite, almandite and hessonite.

Red garnets were made even more popular in the mid-16th century when a large deposit was discovered in Central Europe. It became one of the most widely traded gems by the late 1800s.

Its current retail cost could reach £38,000 at a specialised antiques jeweller.

Garnet rates a 6.5-7.5/10 on the Mohs scale. The Mohs scale of mineral hardness was created by Friedrich Mohs in 1822 and determines the scratch resistance of minerals when scratched by another mineral.

The Mohs scale is used to manufacture everyday objects: your mobile phone’s screen glass is made of a material that scratches at level 6, some at level 7.

Garnets are stable to light and chemicals which make it a popular choice to set in jewellery. However, it should always be cleaned with care as these gems are sometimes treated to make their appearance even more desirable. The most common treatment for this gem would be fracture filled: if there was a small fracture within the stone, it would be filled with resin or similar composite to fill in the gap and make it look “flawless”. The fillings can usually be spotted with a magnifier and causes a flash of light when positioned at the right angle.

In general, it is safe to assume garnets are untreated. But the economic impact on garnets such as demantoid and tsavorite can dictate whether a stone is treated or not. These two types are garnets are often considered to be the most desirable and usually found in small sizes, so their value goes up significantly with size.

Fabergé Platinum Round Demantoid & Diamond Set Halo Ring selling for £34,200. Mounted in platinum, it has a 2.50cts round demantoid garnet with an SSEF certificate indicating it is Russian, and has been heating to enhance colour, and set with 130 round white diamonds totalling 0.90ct.

If the budget doesn’t stretch that high, other garnets, like rhodolite, are far more common in larger sizes.

It’s easy to understand the appeal of garnet. It offers a multitude of different readily available hues to suit all sorts of budget. The key then when choosing an item with garnet is really to think with what outfit would look best with that colour.

Photomicrography – What it is and how it helps us in determining the value of a gem

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As a valuer and gemmologist I work with gemstones daily. Testing, grading and valuing coloured gems is a personal highlight of my work and it was around 5 years ago when testing a Ceylon sapphire that I first fell in love with photomicrography.

I noticed that viewing the stone under the microscope allowed me to dive deeper into understanding the gem and its value. Since then, what was a routine part of gem testing has become a hobby of mine and I can spend hours viewing one gemstone, trying to capture the perfect photomicrograph. In 2021 I was awarded second place in the Gem-A photography competition for this image.

So what is photomicrography?

Put simply, photomicrography is the photography of objects (gemstones in this case) under a microscope.

To begin, I start by thoroughly cleaning the gemstone or item of jewellery I am working on. It’s important not to have any dirt, grease, or dirt on the stone prior to inspection. I will then spend some time viewing the stone in several positions and angles to allow me to find the perfect inclusion scene for my photography. It’s not uncommon for me to spend 30 minutes just getting the perfect lighting and angle for my image. Sometimes I take several photographs at very slightly different focal lengths and then stack the images together using computer software. This can create a sense of depth within the finished piece. This image is made from a stack of 20 photomicrographs.

What can photomicrography tell us about a gemstone?

Natural or Synthetic?

With a higher level of zoom than a jeweller’s loupe, the microscope allows us a more in-depth view of the gem. This can allow us to determine if a gemstone is natural or synthetic; in this image of a synthetic ruby for example where we can see curved striae indicative of Verneuil Flame Fusion growth. In the case of natural stones, we may find crystal inclusions, colour-zoning and/or fingerprints. The microscope can also be a useful step in identifying synthetic diamonds.

Treatments

We can also detect treatments such as coating, dyeing and fracture filling. This image shows a natural ruby which has been lead-glass filled to improve its apparent clarity. This is an important treatment to be able to identify before carrying out any repairs as the filler is unstable and can degrade severely under high heat, like that of a jeweller’s torch – or by cleaning in ultrasonic or steam cleaners. You will see from the image that the surface of the stone appears ‘crazed’ under magnification. At a higher level of magnification we may also encounter bubbles within the glass, another tell-tale sign of treatment.

Heat treatment is considered a standard treatment within the trade for most gemstones but for sapphires and rubies most importantly, evidence of no heat treatment can increase the stone’s value greatly if the stone is otherwise of nice quality. This image shows undissolved rutile ‘silk’ inclusions within a Sri Lankan sapphire. This is evidence of no, or very low heat treatment and allowed me to value the stone accordingly.

In the following image we see amber containing ‘sun spangles’, which are indicative of heat treatment.

Origin Determination

Another important use of photomicrography is determining the origin of a gemstone. In this image we can see a three-phase inclusion which contains a liquid within a cavity, a gas, and a solid which in this case is a calcite crystal. There are also some blocky two-phase inclusions visible. This emerald was determined to be of Zambian origin. Determining the origin of a gemstone allows us to value it more accurately as some localities carry a premium, such as Colombian Muzo emeralds and Burmese sapphires and rubies from the infamous Mogok.

Let’s look at a price comparison to show how origin affects a gem’s value. In the case of this emerald from Zambia, the retail price per carat was £4950. The equivalent stone of same quality but with a Colombian origin would have a retail price per carat of £5850, that’s more than an 18% price difference.

Conclusion

For me, photomicrography is an incredibly useful tool which allows me to accurately value gemstones. But its also become a passion and something I thoroughly enjoy doing. I am always trying to improve on my image quality and find new stones with interesting inclusions which people may not have seen before. If you’d like to see more of my photomicrography, you can check out my Instagram page: Instagram.com/Sammantha_maclachlan_fga_ltd