Garnets are quite a fascinating group of minerals once you get into them. Chemically they are complex and confusing and often very hard to clearly identify what a particular stone is… is it a pyrope, or rhodolite, or almandine? Garnets are found just about everywhere in the world and have a long and ancient history. They have long been popular as jewelry and the cystals much sort after by mineral specimen collectors.
Some of the more familiar types of garnets are :
Pyrope : Red to Brown, RI 1.720 – 1.756, Density 3.62 – 3.87, Mg3Al2(SiO4)3 Magnesium Aluminium Silicate. Name comes from the Greek word “fiery” and has always been a popular fashion stone, once called the “Bohemian Garnet”.
Rhodolite : Red, Pinkish Red to Brown, RI 1.720 – 1.756, Density 3.62 – 3.87, Fe3Al2(SiO4)3 Iron Aluminium Silicate. Rhodolite is a variety of Pyrope and has gained much popularity of late. Some of the nicest rhodolite comes from the Umba Valley in Tanzania and is called Umbalite.
Spessartite : Orange to Red-Brown, Fanta Orange, RI 1.79 – 1.82, Density 4.12 – 4.18, Mn3Al2(SiO4)3 Manganese Aluminium Silicate. It is believed that the name comes from the Spessart in Germany where it is found. Some amazing spessartite comes in a very bright fanta orange colour. Deposits of this material are very small and found in Namibia and Loliondo, Tanzania. This material also goes by the name Mandarin Garnet because of the colour, as well as being called Kunene Spessartine due to the primary source being in the alluvial deposits of the Kunene River between Namibia and Angola. You can see how confusing it can be with all these different names. This fanta orange spessartite garnet is very popular and for good reason… the colour is stunning with fabulous brightness and sparkles, plus this material is getting very rare as the deposits become mined out. Grab this material when you can because it won’t be around forever.
Grossular : Green, Yellow, Brown, RI 1.734 – 1.759, Density 3.57 – 3.73, Ca3Al2(SiO4)3 Calcium Aluminium Silicate. Latin for gooseberry, grossular garnet cuts a very bright light gem. Apparently it has only been known since 1966 in gemstone quality. Varieties of grossular are : Hessonite – a cinnamon brown red orange stone; Hydrogrossular – is an opaque massive green variety, sometimes called Transvaal Jade and Garnet Jade; Leuco – is a colourless variety.
Tsavorite : Deep Green. Is a variety of grossular and perhaps one of the rarest and most expensive of all the garnets. This particular variety is a stunning rich green and tends to be only found in very small stones. Cut gems over 2 or 3 carats are considered scarce and are collector stones. The name Tsavorite was coined only recently in 1974 by Tiffany & Company after Tsavorite’s discovery in the Tsavo National Park, Kenya. Tsavorite garnets are much sort after and compete easily with emeralds – plus they have the great advantage of not being treated (oiled) as virtually all emeralds are. Tsavorite gems have a higher brilliance, fire with lots of sparkles and are more durable. Emeralds are almost always heavily included whereas Tsavorite gems tend to be very clean.
Merelani Mint : Mint Green. This beautiful garnet is a variety of grossular and is closely related to Tsavorite. It is named for the Merelani Hills in Tanzania where it is found. This material is a lovely light mint coloured stone and like Tsvaorite is generally only found in small sizes. It has become very popular and demands a high price due to its scarcity.
Garnet is found in various shades of red, green, yellow, orange and brown. There are even garnets that will change colour under different lighting conditions. For example, in normal daylight they might appear red but under incandescent lights the colour changes to purple or even blue (very rare).
Garnet is the birthstone for January.
Garnet is the ayurvedic birthstone for January.
Garnet is the birthday stone for Tuesday.
Garnet is the zodiac stone for Aquarius.
Garnet is the stone for the 2nd anniversary
Minas Gerais, Brazil; Nigeria, Tanzania, Mozambique, Zambia, Namibia, Africa; Madagascar; USA; India; Burma; Afghanistan; Pakistan; Prosten QLD, Fullerton River, QLD, Harts Ranges, NT, Australia
6.5 – 7.5