Garnet Mineral Information

The history of Garnet dates back to the Bronze Age (more than 5000 years ago), when it was a very popular gemstone. Garnet is a family of minerals having similar physical and crystalline properties. Garnet is found in a wide variety of metamorphic rocks and in some igneous rocks. Garnet is one of the most common nesosilicates but it has a complex structure. The formula for garnet is (Mg, Fe, Ca or Mn) with Al2Si3O12. Garnet is a very commonly found in gneiss and mica slate. Garnet is a very abundant gem and can easily be found in many places around the world. The garnet crystallizes in rhombic dodecahedrons and trapezohedrons. Garnet is a natural abrasive that is still commonly used in woodworking. The name garnet is derived from the Greek word “granatum” or pomegranate seed. One of the oldest gemstones in history, garnet is the birthstone of January.

Garnet is a beautiful stone that comes in quite the range of colors. One popular garnet is chrome pyrope, whose color rivals ruby. Pyrope garnet is the familiar deep red garnet. Garnet is also found in colors ranging from green to orange to brown and black. Almandine garnet is the traditional Indian garnet, which is very dark purplish red. Andradite garnet is usually black and of no interest to the gem trade, but one variety called “Demantoid” is a lively green. The yellowish-green color or the Val Malenco garnet is typical of Fe3+. One of the most sought after varieties of gem garnet are the fine green grossular garnet from Kenya and Tanzania called tsavorite. Mozambique rhodolite garnet is an elite garnet that cuts a bright red with fiery flashes. Hessonite Garnet is a genuine garnet, but with the brown-red or orange color. Malaya Garnet is usually found between Kenya and Tanzania, especially around the Umba valley region that is well known for its buried treasures. Mandarin Garnet is an extreme rarity of the spessartine family.

Almandine is the most common garnet, and the most widely used garnet gem. Almandine, Fe3Al2(SiO4)3 (Iron Aluminum Silicate), is a mineral from the garnet family of tetrahedral silicates. Almandine garnet is a smooth, transparent, rich red stone that owes its color to the presence of iron. Connecticut is one of the finest sources in the world of the almandine garnet, named the state mineral by the 1977 General Assembly. While Almandine Garnets (also known as “Almandite”) are the most common variety of Garnets, those displaying the star are not at all common. Most almandine garnets are mined in India and Brazil. Iron-rich almandine is widespread in metamorphic rocks such as schists and gneisses and in granitic igneous rocks.

Pyrope is the only garnet that is always a shade of red. Pure pyrope is extremely rare and would be colorless (it is allochromatic); most red gem garnet called pyrope contains an appreciable almandine component. This pyrope is one of the so- called “indicator minerals” prized when prospecting for diamonds. Pyrope is commonly purplish red, orange red, crimson, or dark red; and almandine is deep red, brownish red, brownish black or violet-red. It was the Pyrope Garnet that figured in the ancient Talmudic legend, which held that the only light in Noah’s Ark was supplied by an enormous red garnet. The Czech Republic is one of the few places where the Pyrope variety of garnet is found.