Epidote
Epidote is a calcium aluminum iron silicate mineral known for its distinctive pistachio-green color. Unakite — a popular lapidary stone found throughout the Blue Ridge Mountains of Virginia — is a rock composed of epidote, pink feldspar, and quartz with striking pink and green patterns. Alaska produces world-class gemmy epidote crystals from metamorphic terranes on Prince of Wales Island.
Physical Properties
Chemical Formula
Ca₂(Al,Fe)₃(SiO₄)₃(OH)
Hardness (Mohs)
6–7
Color
Pistachio green, yellow-green, black (iron-rich)
Luster
Vitreous to resinous
Crystal System
Monoclinic
Streak
Grey to colorless
Cleavage
Perfect in one direction
Specific Gravity
3.38–3.49
🔍 Field Identification Tips
Pistachio-green to yellowish-green color is distinctive (similar only to actinolite in metamorphic settings). Perfect cleavage in one direction. Hardness 6–7. Striated crystal faces. Unakite (pink and green rock) is commonly found in Virginia and North Carolina streambeds. Distinguished from tourmaline by striation pattern and cleavage.
Varieties & Forms
📍 Where to Find Epidote in the US
Uses & Applications
Collectors specimens, unakite lapidary material, occasional faceted gems.
💰 Collector Value Guide
Common epidote: $5–$30. Quality crystals: $30–$300. Gem transparent crystals (Alaska): $50–$500. Unakite (slab): $10–$100/lb.
Find Epidote With Our Tools
Use the We Lick Rocks app to identify specimens, find dig sites, and connect with local rockhounds.