ID: 17
Chemical Formula
(Zn,Fe)S
Hardness (Mohs)
3.5 - 4
Crystal System
Isometric
Streak
Light brown to yellow, white
Luster
Resinous to submetallic (often adamantine on fresh surfaces)
Diaphaneity
Transparent to translucent to opaque
Color
Highly variable; yellow, brown, black (most common), reddish-brown, green, colorless. Darker colors indicate higher iron content.
Crystal Habit / Mode of Occurrence
Isometric - Hextetrahedral; commonly tetrahedral or dodecahedral crystals, often twinned; also cleavable masses, granular, massive, botryoidal.
Fun Facts
Pure sphalerite is colorless and transparent, but impurities like iron give it a wide range of colors, making it difficult to identify solely by color. Common Uses: Primary ore of zinc (for galvanizing steel, brass production, die-casting alloys), source of cadmium.