Sodalite
Sodalite is a deep blue feldspathoid mineral often confused with lapis lazuli. Its vivid royal blue color with white calcite veining is used extensively as architectural stone. Hackmanite, a rare variety, shows tenebrescence — the ability to change from white to pink or purple when exposed to UV light, then fade back to white. The Bancroft area of Ontario is the world's premier sodalite locality.
Physical Properties
Chemical Formula
Na₈Al₆Si₆O₂₄Cl₂
Hardness (Mohs)
5.5–6
Color
Royal blue, medium blue, gray, green — with white veins
Luster
Vitreous to greasy
Crystal System
Cubic (isometric)
Streak
White
Cleavage
Poor dodecahedral
Specific Gravity
2.14–2.4
🔍 Field Identification Tips
Royal to medium blue with white veins (calcite). Greasy luster. Hardness 5.5–6 (harder than lapis lazuli's pyrite host). White streak. Distinguished from lapis lazuli by absence of pyrite flecks and finer texture. Distinguished from azurite by lower hardness and lack of blue streak. Hackmanite variety glows under UV light.
Varieties & Forms
📍 Where to Find Sodalite in the US
Uses & Applications
Cabochons, decorative carvings, architectural stone (Bancroft Blue), collectors specimens.
💰 Collector Value Guide
Common rough: $5–$30/lb. Quality carvings: $20–$200. Hackmanite (tenebrescent): $50–$500. Premium Bancroft sodalite: $30–$300.
Find Sodalite With Our Tools
Use the We Lick Rocks app to identify specimens, find dig sites, and connect with local rockhounds.