What's That Rock?Hornblende
A dark green to black mineral common in granite and metamorphic rocks. It forms long prisms.
How to identify Hornblende
- Long dark prisms
- Two cleavages that meet at about 56 and 124 degrees
- Harder than biotite
Often confused with
- Black tourmalineno cleavage, triangular
- Biotite
- Pyroxene
Is Hornblende valuable?
Inexpensive.
What changes the price
- Common mineral: low value
- Well-formed black crystals can interest collectors, still inexpensive
Uses
- Rock-forming mineral, specimens
Care
Safe to wash.
Identifying a stone from a description or a photo is an estimate. Many stones look alike. Ask an expert or a gem lab before you buy, sell or rely on an identification.
Updated October 2026