What's That Rock?Andesite
A gray, fine-grained volcanic rock named for the Andes. It sits between rhyolite and basalt.
How to identify Andesite
- Gray, fine-grained, with tiny visible crystals
- Often has pale feldspar and dark hornblende spots
- Between granite and basalt in darkness
Often confused with
Is Andesite valuable?
Common.
What changes the price
- Common rock: almost no collector value as a specimen
- Building and landscaping stone is sold by the ton, not by the piece
- Interesting crystals or textures can make a nice display piece, but they are still inexpensive
Uses
- Road gravel, building stone
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