Garnets are often named after the location where they are found. Umba River garnet is from the Umba Valley of Tanzania. They are a mixture of pyrope and spessartite and display a gorgeous orange-red garnet. It is also known as Umbalite garnet and is a relatively new gemstone to the market.
If you’re contemplating green gemstones, one rare but beautiful alternative to emerald is a Tsavorite garnet.
Tsavorite garnet is one of the most important varieties of grossularite garnet. It was first discovered in 1967 by Campbell Bridges, a Scottish geologist. Tsavorite was named after Tsavo National Park on the border between Kenya and Tanzania, where the stones were discovered.
Tsavorite garnets are about 200 times rarer than emeralds, and they are among the most expensive types of garnets because of their rarity.
These types of garnets also tend to be small in terms of carat size. The majority of stones are under one carat. Pieces over two carats are rare and therefore significantly more expensive than the smaller stones. The most preferred color is a pure, highly saturated green.
Unlike emeralds, inclusions are rare, so Tsavorite garnets don’t typically need to be treated or filled. They have a high refractive index which makes them especially brilliant. They are moderately hard, measuring 6.5 – 7.5 on the Mohs scale.
Rhodolite Garnet from Tanzanite, 6.75mm square radiant cut, 4.35ctw. cut by hand in the Berkshires. This rich purplish-pink color bring out the luster in these 15 x 12mm Fresh Water white baroque drops. Set in simple 18KY double wire baskets with posts and backs. Hand made in our workshop in Lenox.
Floral Applique wedding ring set in 18K yellow gold. The engagement ring can be made with any gemstone. Here we have set a 1.02ct. 6mm round Pyrope Garnet. The rings nest nicely together to form one unique wedding set. Custom made by hand in our workshop.
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms but differ in chemical composition. The different species are Pyrope, Almandine, Umba River, Spessartine, Grossular, Uvarovite and Andradite. Garnet is 6.5 – 7.5 on the Mohs hardness scale.
Spessartine (or spessartite) is named after Spessart in Bavaria, Germany, the type locality of the mineral. Spessartine of an orange-yellow has been called Mandarin garnet and is found in Madagascar. Violet-red spessartine are found in rhyolites in Colorado and Main.
Spessartite, as other garnets, has a hardnes of 6.5-7 on the Mohs hardness scale.
Garnet is January’s birthstone, and the gem for the second wedding anniversary. It is available in a rich palette of colors: greens, oranges, yellows, pinkish oranges, deeply saturated purplish reds, and even some blues.
Red garnet is one of the most common and widespread of gems. But not all garnets are as abundant as the red ones. A green garnet, tsavorite, is rare and needs rarer rock chemistries and conditions to form.
Demantoid is a rare and famous green garnet, spessartite is an orange garnet, rhodolite is a beautiful purple-red, andradite and grossular are a yellowish green color.
All garnets have essentially the same crystal structure, but they vary in chemical composition. There are more than twenty garnet categories, called species, but only five are commercially important as gems. Those five are pyrope, almandine, spessartite, grossular, and andradite. A sixth, uvarovite, is a green garnet that usually occurs as crystals too small to cut. It’s sometimes set as clusters in jewelry. Many garnets are chemical mixtures of two or more garnet species.