mineral
Carnelian
Carnelian (Cryptocrystalline Quartz, SiO2)
Hardness: 6.5 - 7 on Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal microcrystalline). Cleavage: None. Specific Gravity: 2.58 - 2.64.
- Hardness
- 6
- Color
- Orange to reddish-brown
- Luster
- Vitreous to waxy
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Physical properties
Hardness: 6.5 - 7 on Mohs scale. Color: Orange to reddish-brown. Luster: Vitreous to waxy. Crystal Structure: Hexagonal (trigonal microcrystalline). Cleavage: None. Specific Gravity: 2.58 - 2.64.
Formation & geological history
Formation occurs in volcanic cavities and sedimentary rocks where silica-rich groundwater deposits microcrystalline quartz at low temperatures. Its red-orange color comes from impurities of iron oxide (hematite).
Uses & applications
Widely used for jewelry like beads, cabochons, and intaglio seals. It is also used as a gemstone for carving in various cultures and in metaphysical collections.
Geological facts
Ancient Romans used carnelian for signet rings because hot wax does not stick to it. It was once believed to stop bleeding and calm anger. It is a variety of chalcedony.
Field identification & locations
Identify in the field by its distinct waxy luster and translucent orange-red hue. It is commonly found in Brazil, India, Uruguay, and Madagascar. It cannot be scratched by a steel knife.
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