The name "garnet" is named after several related minerals. The unique hues of these minerals result from variations in their molecular composition. Depending on the type of garnet, this may be a single mineral like chromium or a mixture of many chemical components. One of the rarest garnet gemstones is green garnet. While green variants are not much different from red ones in chemical or physical aspects, aluminum, and calcium can be found in both. However, green sapphire may contain chromium and vanadium in minute quantities. Lapidaries further classify green garnet samples into distinct varieties. These are grossular, andradite, and tsavorite, the most widely available green choices, among many others. Count your blessings if you find a Uvarovite or a Demantoid!
The bright green colour of the gemstone is because of the amounts of the elements of chromium or vanadium in its chemical composition. In ultraviolet light, it boasts a fluorescent light cream-yellow colour. Tsavorite formed in a Neoproterozoic metamorphic event which involves extensive folding and refolding of rock. This results in a wide range of inclusions forming within most Tsavorite crystals. These inclusions are strong identifying features in Tsavorite gemstones.
Color: Green
Hardness: 7 – 7.5
Refractive Index: 1.738 – 1.745
Transparency: Transparent
Chemical Formula: Ca3Al2Si3O12
Garnets are known for their color, but their clarity is also important - especially if the stone is lighter colored. Before we discuss opacity, it's helpful to know that there are two groups of garnets: garnets of calcium and garnets of magnesium. Within these two groups, there are six different categories: almandine, pyrope, spessartite, grossular, andradite, and uvarovite. Typical garnet clarity depends on its type. For example, the red garnets almandine, pyrope, and rhodolite typically do not have inclusions visible to the naked eye. Some of the orange garnets, like spessartite and hessonite (a grossular garnet), often have eye-visible inclusions. Rutile inclusions that look like needles within the stone, and are a common type of inclusion in garnets.
As with This type of garnet is very rare and was only discovered in 1967, by the late British geologist Campbell Bridges. The initial discovery was made in Lemshuku, northern Tanzania. Bridges later found a deposit in the Tsavo National park in Kenya and it is after this park that the stone is named. Since then, more deposits have been found in neighbouring Tanzania & Madagascar but are still known as ‘Tsavorites’ in the jewellery trade. all jewellery, keep each piece in a separate box our pouch if you can, or in a box that stops items rubbing against or scratching others. Scientifically, only Sapphire and Diamond would be tough enough to scratch Ruby, but it's always best to keep pieces separate. As always, remove jewellery before exercising, doing housework or when using any harsh chemicals like bleach. When not in use, ensure your Rubies are kept away from heat sources and out of direct sunlight too, though don't worry about wearing your jewellery on sunny days - this is just a storage precaution.
Tsavorite’s are a type of grossular garnet and its trace amounts of vanadium or chromium that give them their colour. The colour of Tsavorites can range from a relatively light, minty green to an intense bright green similar to that of high-quality emeralds.
A super sparkly gemstone, originally discovered in Russia’s Ural mountains, the name ‘Demantoid’ literally means, like a diamond. The exact colour of Demantoid garnets differs depending on which location they are found in and they can have inclusions which actually make them more valuable.
Demantoids are a variety of Andradite garnet and chromium is again the cause of the stones green colouration, whilst Ferric iron is the cause of yellow in the stone. Variations in the exact chemical composition account for the variations in colour.
The most recent addition to the list of garnet varieties of garnet, this lighter shade of grossular garnet is named after the locality in which it is found, Merelani, in Northern Tanzania. It is very similar to Tsavorite garnet but lighter in colour. The Tsavo national park is just 100 or so KM away and in the past, these stones would likely have been described as Tsavorites.