Mohs hardness 7.0-7.5, Specific gravity 3.61-4.05, Refractive index 1.710-1.820. A Silicate mineral. A variety of colours, the most popular being red or green. The garnet group includes a group of minerals that have been used since the Bronze Age as gemstones. The name "garnet" come from either the Middle English word gernet meaning 'dark red', or the Latin granatus ("grain"), possibly a reference to the Pomegranate, a plant with red seeds similar in shape, size, and color to some garnet crystals. Six common species of garnet are recognized by their chemical composition. They are pyrope, almandine, spessartine, grossular (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-grossular-andradite. Garnets species are found in many colors including red, orange, yellow, green, blue, purple, brown, black, pink and colorless. The rarest of these is the blue garnet, discovered in the late 1990s in Bekily, Madagascar. It is also found in parts of the United States, Russia and Turkey. It changes colour from blue-green in the daylight to purple in incandescent light, as a result of the relatively high amounts of vanadium. Other varieties of color-changing garnets exist. In daylight, their color ranges from shades of green, beige, brown, gray, and blue, but in incandescent light, they appear a reddish or purplish/pink color. Because of their color changing quality, this kind of garnet is often mistaken for Alexandrite.
Almandine - a red garnet with a violet tint. Almandine, sometimes incorrectly called almandite, is the modern gem known as carbuncle . The term "carbuncle" is derived from the Latin meaning "live coal" or burning charcoal. The name Almandine is a corruption of Alabanda, a region in Asia Minor where these stones were cut in ancient times. Chemically, almandine is an iron-aluminium garnet the deep red transparent stones are often called precious garnet and are used as gemstones.Almandine has nicknames of Oriental garnet, almandine ruby, and carbuncle.
Pyrope - a red garnet with a brown tint. Pyrope from the Greek pyropós meaning "fire-eyed" is red in color and chemically a magnesium aluminium silicate, the magnesium can be replaced in part by calcium and ferrous iron. The color of pyrope varies from deep red to almost black. Transparent pyropes are used as gemstones. A variety of pyrope from Macon County, North Carolina is a violet-red shade and has been called rhodolite, from the Greek meaning "a rose." In chemical composition it may be considered as essentially an isomorphous mixture of pyrope and almandine, in the proportion of two parts pyrope to one part almandine. Pyrope has tradenames some of which are misnomers; Cape ruby, Arizona ruby, California ruby, Rocky Mountain ruby, and Bohemian Another intriguing find is the blue color-changing garnets from Madagascar, a pyrope spessartine mix. The color of these blue garnets is not like sapphire blue in subdued daylight but more reminiscent of the grayish blues and greenish blues sometimes seen in spinel. However, in white LED light the color is equal to the best of blue sapphire, or tanzanite.
Spessartine - an orange or red-brown Garnet. Spessartine or spessartite is manganese aluminium garnet. Its name is derived from Spessart in Bavaria. Spessartine of an orange-yellow is found in Madagascar. Violet-red spessartines are found in rhyolites in Colorado and Maine.
Andradite - is a calcium-iron garnet, and may be red, yellow, brown, green or black. The recognized varieties are topazolite (yellow or green), demantoid (green) and melanite (black). Demantoid has been called the "emerald of the Urals" from its occurrence there, and is one of the most prized of garnet varieties. Topazolite is a golden yellow variety and melanite is a black variety.
Grossularite - clear, brownish, yellow or green. Grossular is a calcium-aluminium garnet. The name grossular is derived from the botanical name for the gooseberry, grossularia, in reference to the green garnet of this composition that is found in Siberia. Other shades include cinnamon brown (cinnamon stone variety), red, and yellow. Because of its inferior hardness to zircon, which the yellow crystals resemble, they have also been called hessonite from the Greek meaning inferior. One of the most sought after varieties of gem garnet is the fine green grossular garnet from Kenya and Tanzania called tsavorite. This garnet was discovered in the 1960s in the Tsavo area of Kenya, from which the gem takes its name.
Uvarovite - is a calcium chromium garnet . This is a rather rare garnet, bright green in color, usually found as small crystals. It is found in crystalline marbles and schists in the Ural mountains of Russia and Outokumpu, Finland. Uvarovite crystals are generally too small to facet and are left attached to a matrix and incorporated into.