The Birthstone for January: GARNET

Garnets can vary from pink, through red, to orange, yellow, green and black. Recent finds have now added blue to the myriad of colours. So for someone with a birthday in January the choice of colour and colour combinations is vast.

I deliberately headed this blog with a green Mali Garnet to prove the point that the birthstone for January does not have to be red.

But what is Garnet?
What is its scientific nature?
What is its otherworld properties?

Rhodolite Garnet

Rhodolite Garnet


Garnets are a very complex group of gemstones.

They are an Isomorphous series, ie they have the same crystal structure, cubic,  but with varying chemical mix.

This continuous blend can, for example, create a mid way garnet type. For example the popular Rhodolite garnet above is a  Pyrope-Almandine mix.

Garnets can appear as inclusions inside other gemstones, for example as in the image of a diamond below.

Garnet in diamond

Most of the more common Garnets fall into two groups: Pyralspites and Ugrandites. Pyralspites are the aluminum Garnets and Ugrandites are the calcium Garnets.

Pyralspite Garnet Group: The Pyralspites include Pyrope, Almandine and Spessartine. The name Pyralspite comes from Pyrope, Almandine, Spessartite. This includes the vast majority of gemstone garnets.  There is a complete solid solution series between Pyrope, Almandine and Spessartine. These Garnets are often mixed. Malaia is a Pyrope-Spessartine mix and Rhodolite is a Pyrope-Almandine mixture.

 Ugrandite Garnet Group: The Garnets with the widest color range fall into the Ugrandite Garnet Group. are the calcium Garnets.The Ugrandites include Uvarovite, Grossular and Andradite. The name Ungrandite comes from Uvarovite, Grossular and Andradite. There is a complete solid solution series between Uvarovite, Grossular and Andradite. As with Pyralspites these Garnets are often mixed. Grandite (or Mali Garnet) is a mixture of Grossular and Andradite.

 Garnet Physical Properties: General garnet composition: A3B2(SiO4)3, where Ca, Mg, Fe2+, or Mn2+ occupy the A site, and the B site contains Al, Fe3+ or Cr3+. Hydrous garnets may contain up to 8.5% H2O.

Chemical Composition:

Pyralspite Garnet Group

Almandine: Fe3Al2(SiO4)3

Pyrope: Mg3Al2(SiO4)3

Spessartine: Mn3Al2(SiO4)3

Ugrandite Garnet Group

Andradite: Ca3Fe2(SiO4)3

Grossular: Ca3Al2(SiO4)3

Uvarovite: Ca3Cr2(SiO4)3

There are far less common types, which are rarely if ever found in jewellery. There are even garnets from space, such as Majorite which was discovered in a meteorite.

With such a wide diversity in chemical composition other properties such as hardness are varied. The benchmark for hardness is MOHS scale. With Talc at 1 as the softest and Diamond at 10 as the hardest. The scale is (1) Talc, (2) Gypsum, (3) Calcite, (4) Fluorspar, (5) Apatite, (6) Orthoclase feldspar, (7) Quartz, (8) Topaz, (9) Corundum, (10) Diamond.

The most common Garnets have a hardness rating as follows: Almandine (7.5), Andradite (6.5), Grossular (7.0 – 7.5), Pyrope (7.25), Spessartite (7.25), Uvaroite (7.5).

If you are interested in the science of gemmology I can no more than suggest you attend some of the wonderful courses run by the Gemmological Association of Great Britain

Gemmology Association



Garnet on black tourmaline from India

Garnet on black tourmaline from India


Garnets are said to protect the wearer from poisoning and illness of the blood.  Perhaps associated with the blood colour of the common garnet – pyrope.

Also associated with red garnets, in ancient times it was believed to remove anger.

George Frederick Kunz noted this in his wonderful book ‘The Curious Lore of Precious Stones’ (1913) that ‘the symbolism of color played a very important part in recommending the use of particular stones for special diseases’.

It  is further said that it will ensure the wearer is faithful and will speak the truth.
So how much is a garnet worth?
It all depends on type and quality.
Horsehair inclusions
Some garnets by their nature are full of inclusions. A clear pyrope garnet is less valuable than a demantoid garnet with what is known as ‘horsehair’ inclusions. Carat for carat it could be as much as twenty times the value!
This is why it is crucial that the jewellery valuer that you appoint is a qualified and experienced gemmologist. Firstly to determine the garnet type you have in your collection, its quality and its current value.
As a Fellow of the Gemmological Association of Great Britain and a Fellow of the National Association of Goldsmiths Institute of Registered Valuers it is my ethos to ensure that I continue to offer high standards in appraisals.
Managing Director




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A recent lecture that I attended at the Society of Jewellery Historians at Burlington House, given by Nigel Israel, touch upon the bizarre and intriguing robbery of what was considered to be at the time one of the world’s most valuable string of natural pearls.

The key players:


Max Mayer was the most highly regarded and respected pearl merchant in the Garden (Hatton Garden).  Mr Mayer had purchased the pearl necklace in Paris for the then astounding sum of £123,000.  To put this figure into perspective it was a time when a loaf of bread would cost one penny.

He was hoping to sell it for £150,000. So why so valuable? These sixty-one perfectly matched and graded natural pearls were of the finest quality and had taken scores of men over ten years to collect. They were described as flawless and of a rosy delicate pink. Very desirable, very valuable.


Grizard was a fence.  However he was a particularly astute one. He remained out of reach of the law, swanning through the Garden smoking a cigar to give him an air of respectability, whilst at the same time receiving stolen goods from his many followers.

To quote a Scotland Yard police report of the time, ‘He is a diamond merchant by trade, but has no established business premises. He does undoubtedly do a little business, but the greater portion of his time is taken up by organising crimes, and buying and disposing of stolen property. Much has been heard of him during the past fifteen years as having been connected with many serious crimes.  A large number of statements made by prisoners are in our possession showing that they had disposed of their property to him, but unfortunately we have been unable to prosecute him for lack of corroborative evidence.’

This untouchable would use his masterly intelligence to meticulously plan and motivate his followers to carry out the most famous and bold theft of the early twentieth century.


Ex-Superintendent Alfred Leach had been for ten years the Inspector in charge of the Hatton Garden division and knew Cammi and his associates well. Leach had become famous by at one time arresting a pub full of criminals. However in 1908 he retired due to ill health and took a position as a private detective among the Underwriters of Lloyd’s.

He worked mainly for Price and Gibbs, who called him to investigate the stolen pearls.


Mr Mayer had sent the pearls to Monsieur Henri Salomons . However no sale was made and the pearl necklace, together with three further pearls, were packaged and sent by ordinary post as not to attract unwanted attention, to:

Max Mayer, Esq., 88, Hatton Garden, London

On receiving the package Mr Mayer was horrified to find that the pearls had gone and in their place a string of eleven sugar cubes. The cubes weighed the same as the lost pearls and were used to waiver suspicion should the package be weighed again in transit.

Cammi’s minions had intercepted the package and carefully carried out the switch.


A reward of £10,000 was posted. The police, Leach and two amateur detectives tightened the net around Cammi and his gang. What followed next, considering the amount of meticulous planning that had been involved, seems bizarre.

Mr Augustus George Horn, described as a piano forte back maker, whilst walking to work from his home in Islington noticed a small brown parcel lying in the gutter.  He saw a couple nearby catching a bus, called out to them but with no response he placed the parcel in his pocket. Later, on his way to the Swan public house in Islington, he opened the parcel to find a matchbox full of what he thought were marbles. He allegedly gave one to a street urchin to play marbles with before depositing the remainder at the police station.

The question is who threw away the package and why?


Of the sixty-one pearls only fifty-nine have ever been recovered.

The necklace was never to be sold as a single piece again. A few years after its recovery the necklace was divided into three items. One sold in London, one in Paris and the final part in New York.

Wouldn’t it be a fantastic idea to reunite the pearls……………..


‘The Great Pearl Robbery of 1913’ by Christmas Humphreys (1929), published by William Heinemann



If you are interested in pearls I can do more than thoroughly recommend a visit to the Pearls exhibition at the Victoria & Albert Museum, London.  The exhibition contains many of the World’s most famous pearls. My personal favourites are the Pearl of Asia and the Hope Pearl.

The exhibition runs until the 19th January 2014

For more details:




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Lost treasure

Being a keen gemmologist and jewellery historian, perhaps still retaining a little too much of the boy in my soul, the idea of lost treasure mesmerises me.

The scope of hidden and forgotten wonders lost in the fluidity of the world’s ever changing history can pull the most sceptical observer closer. The ‘Three Brothers’ jewel of Queen Elizabeth I, the bridesmaid brooches designed by William Burges and the Charles Du Vé eagle brooches designed for the twelve wedding train bearers of Queen Victoria, immediately come to mind.

If I may digress slightly from the concept of a lost complete jewel and wander into the romantic world of the diamond, and one diamond in particular; The Great Mogul.

The Great Mogul

Let us at once venture back in time to 1665, the first day of November in that year to be precise. The sixty year old French traveller, Jean-Baptiste Tavernier, had recently sold many splendid gems to The Great Mogul, Aurangzeb, the son of Shah Jehan, the fabled builder of the Taj Mahal. Tavernier had remained for two months at Jahanabad and was on that day making ready to leave. Aurangzeb pressed Tavernier to remain and witness the annual festival with the promise of allowing him a viewing of his magnificent gem collection. How could he refuse?

After the festivities on the 10th November he was summoned to the Palace and…….. I will allow Jean-Baptiste to give his account.

‘I found in this apartment Akail Khan, chief of the jewel treasury, who, when he saw us, commanded four of the imperial eunuchs to bring the jewels, which were carried in two large wooden trays lacquered with gold leaf, and covered with small cloths made expressly for the purpose – one of red and the other of green brocaded velvet. …….’

‘…..The first piece which Akil Khan placed in my hands was the great diamond, which is a round rose, very high at one side. At the basal margin it has a small notch and flaw inside. Its water is beautiful, and it weighs 3191/2 ratis, which are equal to 280 of our carats….. When Mir Jumla, who betrayed the King of Golkonda, his master, presented this stone to Shahjahan, to whose side he attached himself, it was then in the rough, and weighed 900 ratis, which are equivalent to 7871/2 carats; and it had several flaws’.

Aurangzeb had hired the Venetian Hortensio Borgio whilst in India to refashion the rough. In The Great Mogul’s eyes Borgio had made a mistake in trying to remove all the flaws and losing two thirds of the weight in the process. Auranbzeb refuse to pay him and instead fined Borgio 10,000 rupees.

This 280 carat diamond became known throughout history as the Great Mogul.

So where is this great diamond today and the large portion of rough that had been cut away?

It is probably that when Nadir Shah looted Delhi in 1739 he took the diamond back to Persia. If this is the case then The Great Mogul was likely to have been stolen on his death in 1747. It may have subsequently been re-cut to avoid detection.

There are those that believe that The Great Mogul, The Orloff and The Koh-I-Noor were all part of the same stone. The history is complex, and at times contradictory. For the interested reader, which much spare time on their hands, I would recommend the reading of Appendix I, in Volume II, of Tavernier’s Travels in India (Ball & Crooke).

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