Guess what! Friday was my thirteenth birthday! And so, I will write a post about my birthstone, Peridot.
Peridot, unfortunately, is one of the semiprecious stones, not one of the precious gems like Diamond, Emerald, Sapphire and Ruby. This basically means that though it is not worth hundreds of dollars per carat, it is still very beautiful.
Peridot is the name for Gem-quality Olivine, which is a mineral composed of (Mg, Fe)2 Si O4. Olivine is formed volcanically, sort of like Granite, but not quite. The lava flows out, the Elements come together, react, and form crystals. In fact, Olivine is very common, so common that some of the sand on Hawaii is actually tiny Olivine crystals formed from the volcanoes on the island. So even though Olivine is a very common mineral, Gem quality Olivine is fairly rare.