Pyrite
Pyrite — "fool's gold" — is actually one of the most treasured mineral specimens when well-crystallized. Perfect cubic crystals from Navajún, Spain are world-famous. In the US, Virginia produces excellent cubic pyrite and Illinois's coal mines yield spectacular pyrite suns (disk-shaped radial growths). Don't be fooled by the nickname — quality pyrite commands serious prices.
Physical Properties
Chemical Formula
FeS₂
Hardness (Mohs)
6–6.5
Color
Pale brass-yellow, gold
Luster
Metallic
Crystal System
Cubic (isometric)
Streak
Greenish-black to brownish-black
Cleavage
Indistinct (conchoidal fracture)
Specific Gravity
5.0
🔍 Field Identification Tips
Greenish-black streak immediately distinguishes pyrite from real gold (gold has yellow streak). Pyrite is much harder (6–6.5 vs gold's 2.5). Pyrite crystals have flat faces; gold is always anhedral. Gold is also much heavier (SG 19.3 vs pyrite's 5.0).
Varieties & Forms
📍 Where to Find Pyrite in the US
Uses & Applications
Historically for sulfur/sulfuric acid production. Today mostly collected as specimens. Some minor use in semiconductors.
💰 Collector Value Guide
Small cubic specimens: $5–$50. Colorado cubic pyrite on matrix: $50–$500. Spanish perfect cubes: $100–$2,000+. Pyrite suns: $20–$200.
Find Pyrite With Our Tools
Use the We Lick Rocks app to identify specimens, find dig sites, and connect with local rockhounds.