What's That Rock?Calcite
A very common calcium carbonate mineral. It is soft, often white or clear, and bubbles in acid.
How to identify Calcite
- Scratched by a copper coin
- Breaks along flat, slanted planes into rhombus-shaped pieces
- Bubbles in vinegar when powdered; strongly in dilute hydrochloric acid
- Clear pieces show double images through them (Iceland spar)
Often confused with
Real or fake?
- Calcite is often dyed or carved as 'Mexican onyx'; hardness and fizz test help
Is Calcite valuable?
Common and inexpensive.
Typical retail prices
Tumbled stone$1–6each
Rough$5–20per pound
Collector specimen$10–100each
Typical retail ranges in US dollars, compiled from public dealer and marketplace listings in October 2026. Real prices vary widely with quality, size and origin. This is general information, not an appraisal.
What changes the price
- Crystal form: sharp, complete crystals beat cleavage chunks
- Color: rare colors (orange honey calcite, pink, blue 'mangano') cost more than white and clear
- Clarity: perfectly clear Iceland spar is prized by collectors
- Size and condition: undamaged display clusters cost most; soft stone chips easily
Uses
- Cement, agriculture and chemicals
- Carvings and ornaments
Care
Soft and dissolves in acids. Avoid vinegar and cleaners on valued pieces.
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