Congratulations, you've just discovered a Rhodolite Garnet Gemstone!
Rhodolite is interesting not only for its chemical composition, but for its unique color. It is a red garnet, but very different from the familiar deep brownish-red of ordinary red garnet. Rhodolite's name comes from the Greek rhodon
meaning rose, and its color ranges from rose red to raspberry red, purple-red and purple-pink.
One of the interesting facts about rhodolite garnet is that it was first discovered in the United States, in the state of North Carolina, around 1898. Even more interesting, it was discovered by mineralogist W.E. Hidden, who also discovered hiddenite, the green variety of spodumene which bears his name.
North Carolina is no longer a significant source for rhodolite. Today the major commercial deposits are in Sri Lanka, Brazil, Zimbabwe, Tanzania, Kenya, Mozambique, Madagascar, and India. Most of the high quality material we've seen recently here in Thailand comes from East Africa.
Since garnet has a hardness of 7 to 7.5 on the Mohs Scale, and indistinct cleavage, it is a durable gemstone that is suitable for all kinds of jewelry. Rhodolite garnet has a high refractive index -- in fact slightly higher than sapphire and ruby -- so it it has excellent brilliance. Rhodolite is one of the more expensive garnets, falling between common red garnet and spessartite in price. But rhodolite, like other garnets, is always untreated.