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Garnet
A garnet crystal
General
Category Mineral
Chemical formula (or Composition) nesosilicates with the general formula A3B2(SiO4)3
Identification
Color virtually all colors
Crystal habit rhombic dodecahedra or cubic
Crystal system Isometric
Twinning ?
Cleavage None
Fracture conchoidal to uneven
Mohs Scale hardness 6.5 - 7.5
Luster vitreous to resinous
Refractive index 1.72 - 1.94
Pleochroism only in certain rare varieties
Streak White
Specific gravity 3.1 - 4.3
Major varieties
Pyrope Mg3Al2Si3O12
Almandine Fe3Al2Si3O12
Spessartite Mn3Al2Si3O12
Andradite Ca3Fe2Si3O12
Grossularite Ca3Al2Si3O12
Uvarovite Ca3Cr2Si3O12
The garnet group of minerals show crystals with a habit of rhombic dodecahedrons and trapezohedrons. They are nesosilicates with the same general formula, A3B2(SiO4)3. The chemical elements in garnet include calcium, magnesium, aluminium, iron2+, iron3+, chromium, manganese, and titanium. Garnets show no cleavage and a dodecahedral parting. Fracture is conchoidal to uneven; some varieties are very tough and are valuable for abrasive purposes. Hardness is 6.5 - 7.5, specific gravity is 3.1 - 4.3, luster is vitreous to resinous, and they can be transparent to opaque.
The name "garnet" comes from the Latin granatus, a grain possibly in reference to malum granatum (pomegranate) a plant with red seeds similar in shape, size and color to some garnet crystals.
There is a misconception that garnets are only a red gem but in fact they come in a variety of colors including purple, red, orange, yellow, green, brown, black, or colorless. The lack of a blue garnet was remedied in 1990's following the discovery of color-change blue to red/pink material in Bekily, Madagascar but these stones are very rare. Color-change garnets are by far the rarest garnets except uvarovite, which does not come in cuttable sizes. In daylight, their color can be shades of green, beige, brown, gray and rarely blue, to a reddish or purplish/pink color in incandescent light. By composition, these garnets are a mix of spessartine and pyrope, as are Malaya garnets. The color change of these new garnets is often more intense and more dramatic than the color change of top quality Alexandrite which is frequently disappointing, but still sells for many thousands of dollars (US) per carat. It is expected that blue color-change garnets will match Alexandrite prices or even exceed them as the color change is often better and these garnets are much rarer. The blue color-change type is mainly caused by relatively high amounts of vanadium (about 1 wt.% V2O3).
Six common varieties of garnet are recognized based on their chemical composition. They are pyrope, almandine or carbuncle, spessartite, grossularite (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series; 1. pyrope-almandine-spessarite and 2. uvarovite-grossularite-andradite.
Garnet is the birthstone for January, and has been used since the Bronze Age.
Garnet
Garnets - aren’t these the wonderfully deep red gemstones which are often found in antique jewellery? Well, this is only the partial truth, as a warm and deep red is indeed the most frequently occurring colour for Garnets. But unfortunately only few people know that
the realm of Garnets holds many more bright and beautiful colours. The traditional image of Garnet has been brightly transformed by spectacular founds, mainly from Africa. Although red remains the major colour, Garnets today easily adapt to any new colour trend in fashion due to the rich range available. And because of the new founds, there are reliable sources for steady supply in these fancy colours. All this explains why this very gemstone family manages to keep on providing new impulses for the jewellery events in our days.
An expert will understand "Garnet” as the denomination for a group of over ten different gemstones with a similar chemical structure. Although the colour red is the one which occurs most frequently, there are also Garnets showing different shades of green, pale to bright yellow, fiery orange and fine earth- and umbra-shades. Only blue is a colour which is not available in Garnet. Garnets are gemstones which are in high demand and are often worked into pieces of jewellery - especially since today not only the traditional gemstone colours red, blue and green are cherished by the consumer, but the intermediate shades and hues are also very popular. Besides the realm of Garnets also possesses rarities such as asterism or atones which change their colour from daylight to artificial light.
What else characterises this gemstone family? First of all, there is the excellent hardness of 7 to 7.5 on the Mohs’ scale. This applies, with minor variations, to all the members of the Garnet group. And this is also an explanation why these gemstones are so excellent to wear. Garnets are quite sturdy and resistant to everyday wear and tear, and uncomplicated to work into jewellery. Only to hard impact or uncontrolled heating they will react adversely. Another point in favour of Garnets is their high refraction of light, the reason for the amazing brilliance of Garnets. The shape of the rough crystal is also interesting. Garnet, after all, means something like "the grainy” and is derived from the Latin word "granum” meaning "grain”. This refers to the typically rounded shape of Garnet and also reminds of the seeds of the pomegranate. In the middle ages, Garnet was also called "karfunkel” in German, referring to the glowing red reminding of the sparks of fire. Today there are a lot of imaginative names used in the trade, such as Arizona Ruby, Arizona Spinel, Montana Ruby or New Mexico Ruby.
The Garnet illuminated already Noah’s Ark
Garnets have been widely known for thousands of years. Even Noah, it is reported, used a lantern from Garnet in order to safely steer his Ark through the darkness of the night. Garnets are found in jewellery from ancient Egyptian, Greek and Roman eras. Many courageous discoverers and travellers wore Garnets for protection, as they were considered popular talismans and protective stones, because it was believed in those days that Garnets illuminate the night and prevent their wearer from any sort of evil. Today science explained to us that the proverbial luminosity of Garnet is caused by its high refraction of light.
Garnets come not onlyy in many colours but also under many names: Andradite, Demantoid, Grossularite, Hessonite, Pyrope, Rhodolith, Tsavorith, Spessartine, Uwarowite etc.. Let us focus on the most important ones, and let us start with red Garnets. First of all, there is fiery red Pyrope. Its fierce and often slightly bronze coloured red was highly popular as gemstone colour in the 18th and 19th century. Worldwide renowned in those days were the Bohemian Garnets from an occurrence in the north-eastern part of the former Kingdom of Bohemia - small stones in a wonderful colour. In Europe they were frequently used for jewellery in Victorian times. This genuine Bohemian Garnet jewellery is traditionally decorated with many small stones which are tightly arranged along each other like the seeds of a pomegranate. Today Garnet is still found in the Czech Republic, and the stones are still arranged in the traditional way, tightly joined, so that the attraction of the classical Garnet jewellery is caused by the beauty of the stones only.
The large central stones of the typical "rosette" arrangements are usually also Garnets, but these come from another category. Almandines, named after the ancient gemstone city of Alabanda in Asia Minor, are c a little different in their chemical structure from Pyropes. Why these are preferred as central stones? Well, Nature only grows Pyropes in small sizes, but allows for Almandine crystals in larger dimensions.
Another red Garnet variety is Rhodolith, a crystal mixture from Almandine and Pyrope This popular red Garnet shows a wonderful velvety red with a fine purple or raspberry coloured undertone. Originally discovered in the USA, it is mainly found in gemstone mines in East Africa, India and Sri Lanka nowadays.
Colourful World of Garnets
The fantastic found of an up to then extremely rare Garnet variety puzzled experts all over the world some years ago. On the Kunene river, on the border between Namibia and Angola, there was the surprising and spectacular discovery of bright orange to red Spessartine Garnets, which were originally named after their occurrence in the German Spessart mountains. Until the legendary mine was discovered in Namibia, Spessartines had existed as mere collector’s items or rarities. They were hardly ever used for jewellery because they were so rare. But the found changed the world of jewellery gemstones. From this time on, an exceptionally fine and brightly orange-red gemstone has completed the offered range. The trade name "Mandarine -Garnet” was coined, and the wonderfully orange coloured Fine Garnet became world-famous almost over night. Unfortunately the mine in the remote Namibian mountains could only be exploited for a few years. Prospecting for the gemstones in the isolated bush land became more and more complicated and expensive It had to be expected, then , that the very upstart among the quality gemstones would only be available in limited amounts from the stocks of few cutters. However, another sensation was caused by discovering another occurrence of the orange-coloured treasures, this time in Nigeria. In colour and brilliance they are so similar to the Namibian stones that only experienced experts will be able to tell them apart.
And now let us focus on green Garnets. Green Garnets - do they really exist? Of course! There are even several known green Garnet varieties. First of all, there is Grossularite, which was created by Nature in many fine colours from yellow to green and brown, and which is especially cherished because of the many in-between shades. And earth-colours. Here there was also a sensational found: In the last year of the 20th century large Grossularite occurrences were discovered in Mali. The Mali Garnets are charming because of their high brilliance, which makes even the usually not so popular brown colour attractive and vivid, and the natural appeal is in wonderful harmony especially with ethno-look inspired trends.
Possibly the most famous green Garnet is Tsavorith or Tsavolith, another Grossularite. Tiffany’s in New York re-named the stone which had been discovered in 1967 by British geologist Campbell R. Bridges in North-East Tanzania. The emerald-green stone was named after its occurrence near the famous game park Tsavo-National Park. Tsavorith is of a vivid light to velvety deep green and, like all other Garnets, of strikingly high brilliance.
The star among green Garnets is rare Demantoid, a gemstone for connoisseurs and lovers. It shows enormous brilliance, higher even than that of Diamond. Russia’s leading court jeweller Carl Fabergé loved the brilliant green Garnet from the Urals more than any other stone, and liked to use it in his creations. Nowadays Demantoid turns up more often in the gemstone market because of the new founds in Namibia. Demantoids from Namibia show good colour and brilliance, however, they lack s minor characteristic: the so-called "horsetail-inclusions”, fine bushy-shaped inclusions which are the characteristic birthmark identifying Russian Demantoids.
A garnet crystal
General
Category Mineral
Chemical formula (or Composition) nesosilicates with the general formula A3B2(SiO4)3
Identification
Color virtually all colors
Crystal habit rhombic dodecahedra or cubic
Crystal system Isometric
Twinning ?
Cleavage None
Fracture conchoidal to uneven
Mohs Scale hardness 6.5 - 7.5
Luster vitreous to resinous
Refractive index 1.72 - 1.94
Pleochroism only in certain rare varieties
Streak White
Specific gravity 3.1 - 4.3
Major varieties
Pyrope Mg3Al2Si3O12
Almandine Fe3Al2Si3O12
Spessartite Mn3Al2Si3O12
Andradite Ca3Fe2Si3O12
Grossularite Ca3Al2Si3O12
Uvarovite Ca3Cr2Si3O12
The garnet group of minerals show crystals with a habit of rhombic dodecahedrons and trapezohedrons. They are nesosilicates with the same general formula, A3B2(SiO4)3. The chemical elements in garnet include calcium, magnesium, aluminium, iron2+, iron3+, chromium, manganese, and titanium. Garnets show no cleavage and a dodecahedral parting. Fracture is conchoidal to uneven; some varieties are very tough and are valuable for abrasive purposes. Hardness is 6.5 - 7.5, specific gravity is 3.1 - 4.3, luster is vitreous to resinous, and they can be transparent to opaque.
The name "garnet" comes from the Latin granatus, a grain possibly in reference to malum granatum (pomegranate) a plant with red seeds similar in shape, size and color to some garnet crystals.
There is a misconception that garnets are only a red gem but in fact they come in a variety of colors including purple, red, orange, yellow, green, brown, black, or colorless. The lack of a blue garnet was remedied in 1990's following the discovery of color-change blue to red/pink material in Bekily, Madagascar but these stones are very rare. Color-change garnets are by far the rarest garnets except uvarovite, which does not come in cuttable sizes. In daylight, their color can be shades of green, beige, brown, gray and rarely blue, to a reddish or purplish/pink color in incandescent light. By composition, these garnets are a mix of spessartine and pyrope, as are Malaya garnets. The color change of these new garnets is often more intense and more dramatic than the color change of top quality Alexandrite which is frequently disappointing, but still sells for many thousands of dollars (US) per carat. It is expected that blue color-change garnets will match Alexandrite prices or even exceed them as the color change is often better and these garnets are much rarer. The blue color-change type is mainly caused by relatively high amounts of vanadium (about 1 wt.% V2O3).
Six common varieties of garnet are recognized based on their chemical composition. They are pyrope, almandine or carbuncle, spessartite, grossularite (varieties of which are hessonite or cinnamon-stone and tsavorite), uvarovite and andradite. The garnets make up two solid solution series; 1. pyrope-almandine-spessarite and 2. uvarovite-grossularite-andradite.
Garnet is the birthstone for January, and has been used since the Bronze Age.
Garnet
Garnets - aren’t these the wonderfully deep red gemstones which are often found in antique jewellery? Well, this is only the partial truth, as a warm and deep red is indeed the most frequently occurring colour for Garnets. But unfortunately only few people know that
the realm of Garnets holds many more bright and beautiful colours. The traditional image of Garnet has been brightly transformed by spectacular founds, mainly from Africa. Although red remains the major colour, Garnets today easily adapt to any new colour trend in fashion due to the rich range available. And because of the new founds, there are reliable sources for steady supply in these fancy colours. All this explains why this very gemstone family manages to keep on providing new impulses for the jewellery events in our days.An expert will understand "Garnet” as the denomination for a group of over ten different gemstones with a similar chemical structure. Although the colour red is the one which occurs most frequently, there are also Garnets showing different shades of green, pale to bright yellow, fiery orange and fine earth- and umbra-shades. Only blue is a colour which is not available in Garnet. Garnets are gemstones which are in high demand and are often worked into pieces of jewellery - especially since today not only the traditional gemstone colours red, blue and green are cherished by the consumer, but the intermediate shades and hues are also very popular. Besides the realm of Garnets also possesses rarities such as asterism or atones which change their colour from daylight to artificial light.
What else characterises this gemstone family? First of all, there is the excellent hardness of 7 to 7.5 on the Mohs’ scale. This applies, with minor variations, to all the members of the Garnet group. And this is also an explanation why these gemstones are so excellent to wear. Garnets are quite sturdy and resistant to everyday wear and tear, and uncomplicated to work into jewellery. Only to hard impact or uncontrolled heating they will react adversely. Another point in favour of Garnets is their high refraction of light, the reason for the amazing brilliance of Garnets. The shape of the rough crystal is also interesting. Garnet, after all, means something like "the grainy” and is derived from the Latin word "granum” meaning "grain”. This refers to the typically rounded shape of Garnet and also reminds of the seeds of the pomegranate. In the middle ages, Garnet was also called "karfunkel” in German, referring to the glowing red reminding of the sparks of fire. Today there are a lot of imaginative names used in the trade, such as Arizona Ruby, Arizona Spinel, Montana Ruby or New Mexico Ruby.
The Garnet illuminated already Noah’s Ark
Garnets have been widely known for thousands of years. Even Noah, it is reported, used a lantern from Garnet in order to safely steer his Ark through the darkness of the night. Garnets are found in jewellery from ancient Egyptian, Greek and Roman eras. Many courageous discoverers and travellers wore Garnets for protection, as they were considered popular talismans and protective stones, because it was believed in those days that Garnets illuminate the night and prevent their wearer from any sort of evil. Today science explained to us that the proverbial luminosity of Garnet is caused by its high refraction of light.
Garnets come not onlyy in many colours but also under many names: Andradite, Demantoid, Grossularite, Hessonite, Pyrope, Rhodolith, Tsavorith, Spessartine, Uwarowite etc.. Let us focus on the most important ones, and let us start with red Garnets. First of all, there is fiery red Pyrope. Its fierce and often slightly bronze coloured red was highly popular as gemstone colour in the 18th and 19th century. Worldwide renowned in those days were the Bohemian Garnets from an occurrence in the north-eastern part of the former Kingdom of Bohemia - small stones in a wonderful colour. In Europe they were frequently used for jewellery in Victorian times. This genuine Bohemian Garnet jewellery is traditionally decorated with many small stones which are tightly arranged along each other like the seeds of a pomegranate. Today Garnet is still found in the Czech Republic, and the stones are still arranged in the traditional way, tightly joined, so that the attraction of the classical Garnet jewellery is caused by the beauty of the stones only.
The large central stones of the typical "rosette" arrangements are usually also Garnets, but these come from another category. Almandines, named after the ancient gemstone city of Alabanda in Asia Minor, are c a little different in their chemical structure from Pyropes. Why these are preferred as central stones? Well, Nature only grows Pyropes in small sizes, but allows for Almandine crystals in larger dimensions.
Another red Garnet variety is Rhodolith, a crystal mixture from Almandine and Pyrope This popular red Garnet shows a wonderful velvety red with a fine purple or raspberry coloured undertone. Originally discovered in the USA, it is mainly found in gemstone mines in East Africa, India and Sri Lanka nowadays.
Colourful World of Garnets
The fantastic found of an up to then extremely rare Garnet variety puzzled experts all over the world some years ago. On the Kunene river, on the border between Namibia and Angola, there was the surprising and spectacular discovery of bright orange to red Spessartine Garnets, which were originally named after their occurrence in the German Spessart mountains. Until the legendary mine was discovered in Namibia, Spessartines had existed as mere collector’s items or rarities. They were hardly ever used for jewellery because they were so rare. But the found changed the world of jewellery gemstones. From this time on, an exceptionally fine and brightly orange-red gemstone has completed the offered range. The trade name "Mandarine -Garnet” was coined, and the wonderfully orange coloured Fine Garnet became world-famous almost over night. Unfortunately the mine in the remote Namibian mountains could only be exploited for a few years. Prospecting for the gemstones in the isolated bush land became more and more complicated and expensive It had to be expected, then , that the very upstart among the quality gemstones would only be available in limited amounts from the stocks of few cutters. However, another sensation was caused by discovering another occurrence of the orange-coloured treasures, this time in Nigeria. In colour and brilliance they are so similar to the Namibian stones that only experienced experts will be able to tell them apart.
And now let us focus on green Garnets. Green Garnets - do they really exist? Of course! There are even several known green Garnet varieties. First of all, there is Grossularite, which was created by Nature in many fine colours from yellow to green and brown, and which is especially cherished because of the many in-between shades. And earth-colours. Here there was also a sensational found: In the last year of the 20th century large Grossularite occurrences were discovered in Mali. The Mali Garnets are charming because of their high brilliance, which makes even the usually not so popular brown colour attractive and vivid, and the natural appeal is in wonderful harmony especially with ethno-look inspired trends.
Possibly the most famous green Garnet is Tsavorith or Tsavolith, another Grossularite. Tiffany’s in New York re-named the stone which had been discovered in 1967 by British geologist Campbell R. Bridges in North-East Tanzania. The emerald-green stone was named after its occurrence near the famous game park Tsavo-National Park. Tsavorith is of a vivid light to velvety deep green and, like all other Garnets, of strikingly high brilliance.
The star among green Garnets is rare Demantoid, a gemstone for connoisseurs and lovers. It shows enormous brilliance, higher even than that of Diamond. Russia’s leading court jeweller Carl Fabergé loved the brilliant green Garnet from the Urals more than any other stone, and liked to use it in his creations. Nowadays Demantoid turns up more often in the gemstone market because of the new founds in Namibia. Demantoids from Namibia show good colour and brilliance, however, they lack s minor characteristic: the so-called "horsetail-inclusions”, fine bushy-shaped inclusions which are the characteristic birthmark identifying Russian Demantoids.
