Topaz
Topaz is one of the hardest silicate minerals and produces beautiful gemstones. Texas has a unique situation — Mason County in the Hill Country produces blue and golden topaz in decomposed pegmatite on private ranch land. Several ranches allow fee digging, and this Texas Blue Topaz is the state gemstone. Colorado's Mount Antero at 14,000+ feet is legendary for white and blue topaz crystals.
Physical Properties
Chemical Formula
Al₂SiO₄(F,OH)₂
Hardness (Mohs)
8
Color
Colorless, blue, yellow, orange-pink (imperial), pink, brown
Luster
Vitreous
Crystal System
Orthorhombic
Streak
White
Cleavage
Perfect basal (one direction)
Specific Gravity
3.49–3.57
🔍 Field Identification Tips
Perfect cleavage in ONE direction (basal) is the key field test — freshly broken topaz shows a flat, glassy cleavage face. Hardness 8. Vitreous luster. Often found with quartz and feldspar in pegmatites. Distinguished from quartz by perfect cleavage and slightly higher SG.
Varieties & Forms
📍 Where to Find Topaz in the US
Uses & Applications
Jewelry (November birthstone, blue), gemstones, collectors specimens.
💰 Collector Value Guide
Texas blue topaz rough: $5–$50/crystal. Cut Texas blue topaz: $20–$200. Imperial topaz (Brazil): $50–$1,000/ct. Mt. Antero specimens: $50–$500.
Find Topaz With Our Tools
Use the We Lick Rocks app to identify specimens, find dig sites, and connect with local rockhounds.