Specimens Strontianite is a rare carbonate mineral and one of only a few strontium minerals.
Crystals are rarer than the massive forms, and so are usually sold as specimens.
Typical specimens have spiky, minute crystals in radiating aggregates or tufts. However, it also forms pseudohexagonal twins similar to aragonite's famous twin. It was mined for a while in Germany for strontium, an element used as a coloring agent of fireworks and other applications. Color is white, colorless, gray, yellowish or greenish. Luster is vitreous to greasy.