mineral
Carnelian
Carnelian Chalcedony (SiO2 with Fe2O3 impurities)
Hardness: 6.5-7 (Mohs); Color: Orange to reddish-brown; Luster: Waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58-2.64
- Hardness
- 6
- Color
- Orange to reddish-brown
- Luster
- Waxy to vitreous
Identified More mineral →
Explore Carnelian in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs); Color: Orange to reddish-brown; Luster: Waxy to vitreous; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific gravity: 2.58-2.64
Formation & geological history
Formed in volcanic environments where silica-rich groundwaters circulate through cavities in lava flows. Its reddish color comes from iron oxide (hematite) impurities.
Uses & applications
Used primarily in lapidary arts for beads, cabochons, seals, and carvings. Also popular in jewelry such as rings and necklaces.
Geological facts
Ancient Romans and Egyptians used carnelian for signet rings and amulets because wax does not stick to its polished surface. It is the birthstone for August in some cultures.
Field identification & locations
Identify by its waxy luster and translucency. It lacks the banding of agate but shares a similar hardness. Common locations include Brazil, India, Uruguay, and Madagascar.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock