Prehnite

Physical Properties

Hardness: 6-6.5 on Mohs scale; Color: Pale green to yellow-green; Luster: Vitreous to pearly; Crystal structure: Orthorhombic; Specific Gravity: 2.80–2.90.

Formation & Geological History

Formed in cavities of basaltic lavas, volcanic rocks, and occasionally in metamorphic rocks through hydrothermal processes. Often found as a secondary mineral.

Uses & Applications

Primarily used as a gemstone for jewelry (cabochons and beads) and as a collector's mineral specimen.

Geological Facts

Prehnite was the first mineral to be named after a person, Colonel Hendrik Von Prehn, who discovered it in South Africa in 1788.

Field Identification & Locations

Identify by its translucent 'bottlegreen' color and characteristic globular (botryoidal) growth habit. Commonly found in South Africa, Australia, and the USA (New Jersey).

Identified on: 4/22/2026

Mode: Standard