mineral
Carnelian (Chalcedony)
Silicon Dioxide (SiO2) with Iron Oxide impurities
Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (microcrystalline); Cleavage: None; Fracture: Conchoidal.
- Hardness
- 6
- Color
- Translucent orange to reddish-brown
- Luster
- Vitreous to waxy
Identified More mineral →
Explore Carnelian (Chalcedony) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 6.5-7 (Mohs scale); Color: Translucent orange to reddish-brown; Luster: Vitreous to waxy; Crystal structure: Hexagonal (microcrystalline); Cleavage: None; Fracture: Conchoidal.
Formation & geological history
Forms in pockets of volcanic rock, where silica-rich groundwater deposits minerals over time. Its color is derived from iron oxide (hematite) impurities. Often found as water-worn pebbles in stream beds.
Uses & applications
Used primarily in lapidary work, jewelry (beads, cabochons), and as a collector's stone. Historically used for signet rings and wax seals because hot wax does not stick to it.
Geological facts
Carnelian was revered by ancient Egyptians as the 'setting sun' and was mentioned as a protective stone for the heart. It is one of the oldest gemstones recorded in history, dating back to the Neolithic period.
Field identification & locations
Identify by its translucent, waxy appearance and orange color range. Found commonly in Brazil, India, Uruguay, and Madagascar. In the field, look for smooth, rounded pebbles that appear glowing or translucent when held to the light.
More like this
Other mineral specimens
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Sandstone with Mineral Veining or Crust
Sedimentary Sandstone (mostly SiO2 with Fe2O3 tinting)
sedimentary
Schist
Schist
Metamorphic
Potassium Feldspar (Orthoclase)
Orthoclase (KAlSi3O8)
mineral
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic