Group: Silicates - inosilicates
Chemical composition: Ca2(Mg,Fe)5Si8O22(OH)2Cr
Colors: White, light to dark gray, light yellow, light to dark green, light pink to light purple. Rarely colorless
Hardness: 5 to 6
Formation: Vitreous, silky luster
Principal Sources: Colorado, New York, Connecticut, Italy, Switzerland
Special Notes: Tremolite rich in the element chromium, giving it an emerald-green color.