Chemical Formula: NaCa2Si3O8(OH)
Class: Silicates
Hardness: 4.5-5
Coloration: All colors of the spectrum as well as colorless and black.
How to identify it/Unique Characteristics or Properties: This is a very complex mineral group with a wide variety of colors, but all are crystals with a triangular or close to triangular cross section. Often has banded colors, with one color blending into another along the length of the crystal. Each color has its’ own name, as they often resemble other gemstones. Can grow up to a meter long and several inches wide.
Where to find it in…
The Northwest: The South Santiam River in Oregon
Other: Widely found, Dominican Republic, Canada, England, Italy
Past Uses: Mainly just collected for being interesting. At times, a rare blue variety from the Dominican Republic is also used in jewelry like turquoise.
How it was Made: Primarily formed in hydrothermal vents in basaltic rock
Interesting Facts: When fractured the splinters are extremely brittle and dangerously sharp.