Mohs Hardness: 7
Specific Gravity: 2.65
Reflective Index: 1.544-1.553
Smoky quartz is a macrocrystalline variety of the mineral Quartz (SiO2). Quartz is the most abundant single mineral on earth.It makes up about 12% of the earth's crust, occurring in a wide variety of igneous, metamorphic and sedimentary rocks. Quartz varieties are commonly separated into two groups based on the size of the individual grains or crystals; macrocrystalline quartz in which individual crystals are distinguishable with the naked eye, and cryptocrystalline quartz in which the individual crystals are too small to be easily distinguishable under the light microscope.

Smoky Quartz has only one color: