Turquoise

The December birthstone is Turquoise, a blue to green minerals which is moderately hard and typically shows no specific crystal structure. Turquoise is a 6 on the Mohs Hardness Scale of 1 to 10, has a pale blue to white streak, and a waxy luster. “Cryptocrystalline” is the term often used for minerals like turquoise where the crystals are so small that they can not be seen.  Turquoise can be nicely polished and is therefore, used often in jewelry.