Hardness: 7 (Mohs)
Specific Gravity: 2.65
Chemical Composition: SiO2
Refractive Index: 1.544 - 1.553
Mineral Information: Macrocrystalline quartz
Quartz crystal was once believed to be an eternal ice sent by the heavenly gods. Until the late 1500s, many scholars thought this stone was fossilized ice. Quartz crystal is actually a mineral, one of the most abundant minerals in the Earth's continental crust, composed of silicon and oxygen.