Mineral Guide · Mineral variety
Carnelian is a red to orange chalcedony variety of quartz, coloured by iron and valued as a durable ornamental stone.
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Carnelian is a red to orange chalcedony variety of quartz, coloured by iron and valued as a durable ornamental stone.
The reference formula is SiO2. Carnelian is classified with the silicates and its crystal system is trigonal. Natural specimens can vary in composition, habit and degree of crystallinity, so the locality and observed form remain important.
Typical colours include orange, red-orange, reddish brown and brown. Lustre, transparency, inclusions and surface condition should be described for the individual specimen rather than inferred from the name alone.
Carnelian forms in or is associated with silica-rich cavities, volcanic rocks and sedimentary gravel deposits. Notable collecting regions include India, Brazil, Uruguay, Madagascar, Botswana and Germany. A precise locality is more useful than a broad country label when it is documented.
Carnelian is useful in a reference collection because its appearance connects mineral chemistry with geological setting. Store specimens dry, protected from impact and clearly labelled with the confirmed material, locality and any treatment history.
Reviewed by NotOnlyRocks Editorial Team
Last reviewed: 31 August 2026
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