What's That Rock?Siderite
An iron carbonate that is tan to brown and often forms rounded crystals or nodules. It is an iron ore.
How to identify Siderite
- Brownish rhombohedral crystals
- Heavier than calcite
- Fizzes in hot or powdered form with acid, weakly in cold
Often confused with
Is Siderite valuable?
Inexpensive.
Typical retail prices
Collector specimen$8–80each
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
- Crystals: sharp, lustrous crystals on matrix cost more than massive pieces
- Color and size: clean, undamaged display clusters are worth more
- Common iron ore: ordinary pieces are inexpensive
Uses
- Iron ore
Care
Slowly turns brown and rusty in damp air.
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