All About Garnets

Garnet Facts

The word Garnet comes from the Latin, 'granatus' meaning grain. This is a possible reference to the pomegranate fruit which has seeds of a similar shape size and color to some garnet stones.

Although many people think of garnets as green garnets are in fact, usually red in color but can also be found in a number of other colors including purple, orange, yellow green brown and even black. Even colorless crystals of garnet have also been found.

In the 1990s a color change garnet blue to red/pink material was found in Bekily, Madagascar. However these are extremely rare. In daylight the color can be shades of green, beige, brown, gray and rarely blue which then change to a reddish or purplish/pink color in incandescent light. These garnets are composed of 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 garnets which sell for many thousands of U.S. dollars 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.

The garnet is a beautiful stone that has been in use since the Bronze Age and is the birthstone for January.

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, is of strikingly high brilliance.

The garnet group of minerals show crystals with a habit of rhombic dodecahedrons and trapezohedrons. They are nesosilicates with the same general formula, X3Y2(SiO4)3 in which the X site is usually occupied by divalent cations (Ca, Mg, Fe2+) and the Y site by trivalent cations (Al, Fe3+, Cr). 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, lustre is vitreous to resinous, and they can be transparent to opaque. The name "garnet" comes from the Latin granatus ("grain"), possibly a reference to the malum granatum ("pomegranate"), a plant with red seeds similar in shape, size, and color to some garnet crystals.

Garnets are most commonly red in color but can be found in a variety of colors, including purple, red, orange, yellow, green, brown, black, or colorless. The lack of a blue garnet was remedied in 1990s 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 U.S. dollars 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.