January Birthstone, Garnet

January 2010

By Janet Deleuse of Deleuse Jewelers, Tiburon, California

The gemstone Garnet brings to mind a vision of sparkling little red stones set in clusters of florets worn by our great grand mothers. The small bright red rounds resemble pomegranate seeds which is exactly what they are named from the Latin word for pomegranate seeds, ‘Granatum.’

Trio of Garnets: Tsavorite, Malaya and Spessaritite Designed by Janet Deleuse

Amazingly, garnets are in all colors except shades of blue.

Some of the most beautiful and important rare gemstones are garnets with vibrant orange, green and magenta colors. The garnets are a durable stone and exhibits a lively light reflection. In fact, in the legend of Noah’s Ark, according to the Talmud, states that a single large garnet provided the only light source for the Ark.

The nomenclature for the group of minerals which have a common crystal structure and a similar chemical composition is garnet. Within the garnet family there are several common names, depending on the chemical compositions, for the different colored garnets. Of the six types of crystals only five are large enough to be used in jewelry. The garnet crystals form in a cubic system with a twelve-faced rhombic dodecahedron and the twenty four faced icostetrahedron and in combinations of these two forms.

Garnets have been found in excavations throughout the world. They were used by the Egyptians for inlaid design and fashioned into beads approximately 3100 BCE. And before them the Sumerians wore garnets in 2300 BCE. In Sweden garnets were found to be treasured in 2000-1000 BCE. The Grecians and the Romans also used garnets as amulets and intaglios (carved stones), primarily as rings.

Almandite garnet is the most common color ranging from medium red to dark brownish red. The color is due to the content of iron-aluminium silicate. The inhabitants of the ancient city in Asia Minor, Alabanda, originally named the Almandite garnet where excavations have found garnet jewelry popular in the fourth century BCE. Today the main source is India. India has been one of the main sources as early as 3200 BCE discovered in Egypt. Unusual to the other types of garnets, a cabochon cut of the Almandite garnet will reflect a ‘star’ pattern of light called asterism, (similar to that of ruby and sapphire.)

Bohemian style Garnet jewelry

The name pyrope is derived from the Greek word “pyropos” which means fire like because of the fiery reflection and deep saturation of red. Nicknamed the ‘Bohemian’, the pyrope garnet was found originally in the old kingdom of Bohemia, now known as the Czech Republic. Excavations have uncovered garnet necklaces from as early as the Bronze Age in this area. The old style of cutting and jewelry design was one of the main source of employment in the region and can be traced back to the sixteenth century. This type of work became very popular again in Victorian jewelry as they fashioned garnet ’roses’ into earrings, pins, rings, tiraras and ornate drop necklaces.

The pyrope garnet has a deep red color with a tint of purple. They are also a brownish red color (similar to the almandite variety.) The elements for coloring a pyrope garnet is magnesium-aluminium. The pyrope garnet is often found near diamond supplies. Large pebbles of garnet found on the ground in the Kalahari desert led to discovery of diamond mines. Also in Russia, the discovery of pyrope garnet in 1953 instigated a search for diamonds where the first kimberlite pipe (diamonds) was located in the upper Markha river.

Following the termites in the Arizona, New Mexico and Utah deserts of the U.S. the Native Americans discovered the pyrope garnets. Native Americans used garnets to decorate the headdresses and for ornamentation. The garnets used by the Aztecs were traded from the Native Americans.

The main source for the pyrope garnets today are from Africa.

Pyralspite is the term for an intermediate series of garnets which are a mixture of minerals that do not fit into a specific garnet family. Rhodolite garnet is a mixture of pyrope and almandite. Named after the beautiful violet red to pink red color of the rhododendron flower, the rhodolite garnet is an unusually beautiful color. Originally found in North Carolina in 1882 where the rhododendron plant is abundant. There are a few rare rhodolite garnets from East Africa that have the star reflection.

The Malaya, Swahili word meaning prostitute, is a mixture of spessartine and pyrope. Discovered in 1979 this incredibly beautiful stone has hues of orange to reddish orange with pinkish overtones and became very popular for jewelry.

The rare orange spessartine or spessartite, is of manganese-aluminum silicate andratie which gives it the intense beautiful color. Originally discovered in the district of Spessart, near Schaffenburg, Bavaria the gem has been called spessaritite. Spessarite garnet can be vibrant yellow but more commonly it is a yellow brown color and often confused with the citrine or topaz.

Named after the Portuguese mineralogist M. d’Andrada who named the gem ‘allochroite’ in 1800, the Andradite garnets varies in many colors from black to shades of yellow and green. The lively green and rare demantoid garnet is the most valuable of all the garnets. In fact the name, demantoid is derived from the old German word for diamond, ‘Demant’ because of the similar firey sparkle due to the color dispersion. Demantoids were often incorrectly called “Olivine” in the past years. The intense green is comprised of calcium-iron silicate, with the trace of chromic oxide which makes the green unique to garnets. Originally found in the Ural mountains of Russia in 1851 the gem has been used for fine jewelry. The gem buyer for Tiffanys, George Kunz, purchased all the demantoid garnet available at that time which is the reason that many of Tiffanys fine jewelry has some of the finest green garnets. Found in small sizes the demantoid is rarely over four carats.

Antique Tsavorite Garnet Necklace

Grossularite garnets are the variety of many different colors ranging from colorless, white, yellow, violet-red and orange red. The name grossular is not used for an individual garnet because it is the mineralogical name for the calcium aluninium group. Each of these colors may be called by a separate name such as hessonite which ranges in orange to brown colors. Nicknamed ‘cinnamon stones’ the earliest known source of hessonite garnets are from the ‘spice island’ of Sri Lanka. South Africa, Tanzania and Kenya has also been a source of the emerald clear green tsavorite garnet. Discovered in 1968, in the Tsavo National Park in Kenya, the Tsavorite was promoted and used extensively by Tiffanys. Tsavorite garnets are very rare.

Translucent grossularite may be confused with jadeite or misnamed as “South African Jade.” Found in Transvaal it is also erroneously called “Transvaal Jade.” Some of this material may be grey or pink and the texture is opaque and may have black specks.

The one variety which never grows in crystals large enough for jewelry is called uvarovite which has a clear deep green color comprised of calcium chromium.

In 1892 the Hanzas used garnet bullets against the British troops during the hostilities on the Kashmir frontier based on their ancient belief that garnet bullets are more deadly than those of lead. Some of these bullets are in museums today for preservation.

Garnets represent faith, truth and the release of melancholy.


Additional Information and Photo Credits:

National Gem Collection, The Smithsonian Institution, Jeffry E. Post with photographs by Chip Clark, 1997

Gems, Their Sources, Descriptions and Identification, Fifth Edition, R. Webster, Butterworth and Heinemanne 1962

Gems, Crystals, & Minerals, Anna S, Sofianides, George E. Harlow with photographs by Erica and Harold Van Pelt, Simon and Schuster, New York 1990