Quartz crystals was one of the earliest known minerals, and one of the most common.

Chemical Formula: SiO2
Class: Silicates, Tectosilicates
Hardness: 7
Coloration: Colorless to rose pink, yellow, brown, and green.

How to identify it/Unique Characteristics or Properties: Quartz crystals was one of the earliest known minerals, and one of the most common. It is a crystal that ranges from small to huge, and can come in a whole host of colors depending on trace elements added in. Many of the colored versions of quartz have their own name. Amethysts are purple quartz crystals who got their coloration from radiation. Citrine are yellow because of FeOOH, rose quartz are pink from rutile needles, aventurine is green because of chronian, and tiger’s eye is a striped version because of small strands of asbestos. The clear versions are called rock crystals.

Where to find it in…

The Northwest: Almost everywhere, extremely common.
Other: As the second most common mineral in the Earth, it is found nearly everywhere, especially near granite deposits.
Past Uses: Used heavily in jewelry, glass manufacture (as nearly pure silicone), and electronics for accurate timing.
How it was Made: Quartz mainly forms in magma, and is so hard that as other elements erode away, it stays. Larger crystals generally form near hydro thermal vents and geodes.
Interesting Facts: Quartz has some very strange electrical properties. If pressure is applied to a crystal it gets a positive electrical charge on one end and negative on the other. Quartz also vibrates if an electrical current is passed through it. This vibration is very regular and used as a chronometer in watches.