The warm and fiery glow of the traditional Garnet makes it a perfect birthstone for the wintry month of January. But if red is not your color, don’t worry: Garnet comes in a wide variety of colors. You will find this stone in antique, vintage, and contemporary jewelry pieces, in a wide variety of forms and fashions.
Garnets are actually a large family of related silicate minerals. The name itself is based on the Latin granatus, meaning grain. This is probably a reference to the pomegranate, which has red seeds which resemble some Garnet. The Garnets which are most familiar to most of us are two of the traditional reddish varieties, pyrope and almandine.
This is the traditional “Bohemian Garnet”. With a name which translates as “similar to fire”, some of these dark red garnets just glow. The material occurs in darker color ranges as well, even black. While lots of good gem quality material is available in sizes under 5mm, larger specimens, especially in better colors, are rarer. Some of the best specimens show a color which rivals Ruby or Red Spinel, and these are sometimes referred to as Chrome Pyropes. Found in the Czech Republic, South Africa, Australia, and the United States, these aluminum-magnesium garnets are sometimes marketed as Colorado Ruby, Cape Ruby, and Arizona Ruby, all improper misnomers.
This variety, also known as Almandite, is the most common of the gem Garnets. The iron-aluminum garnet is named after the city of Alabanda, where they were cut in ancient times. They are sometimes referred to as “carbuncles”, a name which means “little spark”. India, Sri Lanka, Madagascar and Brazil are major sources for the stone, but they are found in other areas, including the United States. These red gems are sometimes marketed as Oriental Garnets or Almandine Ruby, which is an inappropriate term.
Moving away from the fiery red varieties, we discover a rainbow of colors.
Pure Pyrope or Almandine Garnets are rare. Most are combinations of the two minerals to some extent, with iron and magnesium atoms substituting for one another. Rhodolite Garnet is such a hybrid, with about 2 parts Pyrope to 1 part Almandine. The violet-reds and lilac-reds exhibited by this stone have made it very popular. Found in Sri Lanka, Tanzania, Zimbabwe, Madagascar and the United States, this Garnet is sometimes incorrectly represented as Cape ruby, Arizona ruby, California ruby, and Rocky Mountain ruby.
This gem variety of Grossular Garnet has been popular since it was discovered near Tsavo National Park in Kenya in 1967. Tiffany & Company was very instrumental in introducing this gem to the buying public. It has a distinct clean, crisp green appearance, which can be confused with some of the finest Green Tourmaline.
Another gem variety of Grossular Garnet is known as Hessionite. The reddish yellow stone may have been referred to as jacinth or hyacinth in some older gem references.
Varieties of Grossular Garnet are found primarily in Sri Lanka, Kenya, and Tanzania, but also in Brazil, Canada, India, and the United States.
Traditionally found in the Ural Mountains, this brilliant green Garnet was favored by Peter Carl Faberge, master of Russian Goldsmiths. Until recently, this stone was rarely encountered outside of the realm of antique pieces. Recent finds in Namibia have made more stones available. The Russian stones often exhibit a signature “horse tail” inclusion, absent from the newer African material. This gem is a variety of Andradite Garnet. Other gem varieties of Andradite include a yellow variety, Topazolite, which may show a chatoyant cats-eye effect, and Melanite, a black variety.
Originally found in Germany, near Spessart, this gem was rather rare until larger finds turned up in Africa, where Nambia, Angola, and Nigeria have all produced some nice orange and orange-red stones. Sometimes this material is marketed under the acceptable trade name of Mandarin Garnet or Mandarine Garnet. This magnesium-aluminum garnet is also found in Brazil and Sri Lanka.
This variety was first identified as Garnet in the 1960’s when large finds on the Umba River in Tanzania and Kenya were reported. This orange variety is considered a mix of Pyrope and Spessartite, but may include a little Almandine and a touch of Grossular in the mix. This variety is nearly a “night stone”, as its appearance is often better in incandescent light than in natural sunlight.
BLUE GARNETS ?
For years it was accepted that garnet came in all colors except blue. This is no longer true. Blue Garnets, which appear to be a Pyrope and Spessartite mix, have been documented, with Madagascar listed as a source.
This green variety, with a resemblance to Jade, is sometimes used in jewelry. The material is sometimes incorrectly identified as South African Jade or Transvaal Jade.
Uvarovite is a green variety of calcium chromium Garnet which sometimes sees use in jewelry pieces.
If all the variety in color is not enough for you, garnet also exhibits some special effects. Garnet may exhibit the star-like effect of asterism or exhibit the cat’s-eye effect known as chatoyancy. Star garnets are found in India and Idaho, with stones producing a four-rayed star under strong proper lighting. Idaho seems to be the only source for the six-rayed stones. The effect is produced by inclusions of rutile needles. The cat’s-eye effect is very rare, and seems to only occur in the Topazolite variety of Andradite Garnet.
Garnet may also exhibit a color change which mimics that of Alexandrite. Some stones will change from a grayish-green or purplish green to a reddish-pink or reddish-purple or lavender. This change seems limited to the variety of pyrope-spessartine Garnets known as Malaya Garnet.
There are two man-made Garnets which have seen use in jewelry. Neither actually has a natural counterpart, so man-made is probably a more appropriate term than synthetic. Yttrium aluminum garnet and gadolinium gallium garnet have both been used as Diamond simulants.
While it is sometimes possible to identify garnet with reasonable certainty by some natural inclusions in the stone, most definitive Garnet testing involves measuring the refractive index of the stone or an analysis of the absorption spectra of the stone. Since some varieties are a hybrid mixture of various Garnets, separation of individual varieties is a little problematic without gem testing equipment. It is quite acceptable to describe any known garnet simply as Garnet, without identifying the particular variety.
Garnet is one of few gemstones which is not being enhanced to improve its color, with no known treatments currently.
In addition to its use as a gemstone, low quality garnet has found use as an industrial abrasive. Garnet is also used in specialized fields of geology to obtain clues about the heat and pressure history of surrounding materials. In some parts of the world, the presence of certain varieties of Garnet indicates the presence of Kimberlite, which indicates the possibility of Diamonds in the area.
The hardness of Garnet varies a bit, due to the differences in actual composition, ranging from 6.5 to 7.5 on the Moh’s Scale. Steam cleaning should never be done to garnet jewelry. Ultrasonic cleaning is considered to be normally safe, but the presence and type of inclusion in the stone may have an effect on durability, and we do not recommend the practice.
SHOPPING FOR GARNETS
You will find Garnets available in a wide range of styles and prices. From Classic Victorian pieces featuring Pyrope “Bohemian Garnets” or Demantoids to contemporary Artisan pieces featuring some of the less well-known members of the Garnet family, pieces are available on Ruby Lane in all styles, and in a wide range of ages and prices.