Brazilian Quartz with Hematite Inclusions (A075)
A cluster of quartz crystals with hematite inclusions from Brazil.
Quartz is a hard, crystalline mineral composed of silicon and oxygen atoms. It is the second most abundant mineral in Earth's continental crust, behind feldspar. There are many different varieties (i.e. colors) of quartz, several of which are semi-precious gemstones. Since antiquity, varieties of quartz have been the most commonly used minerals in the making of jewelry and hardstone carvings, especially in Eurasia. The word "quartz" is derived from the German word "quarz.”