mineral
Carnelian (Chalcedony)
Silicon Dioxide (SiO2)
Hardness: 6.5-7 Mohs; Color: Reddish-brown, orange; Luster: Vitreous to waxy; Structure: Cryptocrystalline (Trigonal); Cleavage: None; SG: 2.58-2.64
- Hardness
- 6
- Color
- Reddish-brown, orange
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5-7 Mohs; Color: Reddish-brown, orange; Luster: Vitreous to waxy; Structure: Cryptocrystalline (Trigonal); Cleavage: None; SG: 2.58-2.64
Formation & geological history
Formed through the deposition of silica from groundwater in cavities of igneous rocks (basalts), often associated with volcanic environments.
Uses & applications
Primarily used as a semi-precious gemstone in jewelry, beads, and carved cameos due to its durability and color.
Geological facts
Carnelian was used by ancient Egyptians for protective amulets and by Romans for seal rings since it does not stick to hot wax.
Field identification & locations
Identify by its translucent reddish-orange hue and waxy luster. Commonly found in riverbeds or beaches in Brazil, India, and Uruguay; check for conchoidal fracture.
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Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Schist
Schist
Metamorphic
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Gypsum (variety Selenite or Alabaster)
Calcium sulfate dihydrate (CaSO4·2H2O)
Mineral
Nephrite Jade
Nephrite
Mineral/Rock
Granite
Granite (Phaneritic intrusive igneous rock)
igneous