Varieties of Garnet
Because of their variable mineral structure, garnets come in a dazzling array of types and colors. In fact, the only color they don't come in is blue! Not all varieties of garnet are suitable for use in jewelry - some opaque forms can be carved like jade, some types are used for industrial purposes and others have no real use at all - but the 7 kinds of garnet listed below have all found their rightful place in the world of jewelry fashion!
One of the most popular types of garnet, Almandine, is an orange-red to brown colored stone first mined in Alabanda, from which it takes its name. Almandine garnets sometimes contain inclusions of asbestos fibers, which create a star effect when cut. Almandine garnets were popular in Victorian jewelry.
Pyrope (from the Greek for "Fiery"), is a dark, blood-red variety of garnet. It is also called "Bohemian Garnet" and was used extensively in jewelry manufactured in Czecheslovakia in the 18th and 19th century. A variety called Chrome Pyrope is found in Arizona - it's color is a rich red similar to that of the ruby.
Very few of the deep red garnet gemstones used in modern jewelry are pure Almandine or pure Pyrope- they are actually a combination of the two varieties.
Less common than Almandine or Pyrope, Spessartite garnets are orange to reddish brown in color. As is the case with red garnets, few gemstones are pure spessartite - instead they are more frequently a combination of spessartite and almandine. The more spessartite in the gem stone, the more orange the color.
A highly-prized variety of spessartite is the Mandarin garnet - a brilliant, mandarin orange stone found in Namibia.
Another popular gemstone variety of garnet is Rhodolite - a violet-hued red garnet in colors ranging from light magenta to purple and red-violet. Rhodolite garnet is a combination of Almandine and Pyrope.A notable source of Rhodolite is in North Carolina, but it is also found in Brazil, India and Asia.
A similar Almandine / Pyrope blend produces up the popular Mozambique garnets. Found primarily in (where else?) Mozambique, these garnets are somewhat redder and darker than than their cousin, Rhodolite.
Tsavorite (Green Garnet)
Tsavorite garnet is the name given to this treasured green variety garnet, first discovered in 1967 in Tanzania's Tsavo National Park. Actually a variety of grossular garnet, the popular name tsavorite was bestowed upon this gemstone by Henry Platt - president of Tiffany & Co. and the great grandson of Louis Comfort Tiffany.
Tsavorite is typically a vivid and very beautiful emerald green, occasionally with a blue-ish or yellow-ish cast. Intense, mid-tones of green are the most sought-after. The exquisite tsavorite is both rarer and more brilliant than it's color-lookalike, the emerald.
A grossular garnet like Tsavorite, Hessonite is honey-colored or golden-orange to reddish brown in color. It is also called the cinnamon stone.
A treasured gemstone from the Ural mountains of Russia, the Demantoid garnet (a special variety of Andradite garnet) is a green garnet with some very unique properties/ It's name means "diamond like", and like the diamond the inner structure of the demantoid garnet lends it a unique and exquisite sparkle - sometimes even surpassing the brilliance of a diamond!
Some demantoid garnets contain feathery inclusions of the mineral byssarite which are called horsetail inclusions. These are considered to further enhance the beauty of the stone and add to it's value.
"Color Change" Garnets
As the name implies, color change garnet is the name given to garnets with special properties that cause them to appear as different colors under different types of light - a property they share most notably with the gemstone Alexandrite. Most color change garnets are mined in Africa - in Madagascar and Kenya.
The color change can be a subtle shift in color or it can be more dramatic, displaying two completely different colors. This phenomenon is thought to be caused by a number of factors, including chemical variations and a balance of transmission maxima in the stone, the range of colors being observed in conditions in which light is transmitted as opposed to others where light is reflected in the stone.
Color change garnets lend a beautiful sparkle to a ring or a pendant and are also sought after by gem stone collectors. Green to gray or reddish-brown to gray stones are the most common, stones with a major color shift such as purple-aqua or extremely scarce blue-magenta specimens are much rarer and much more costly.