mineral

Carnelian Agate

SiO2 (Silicon Dioxide with Iron Oxide impurities)

Hardness: 6.5-7 (Mohs). Color: Translucent orange to reddish-brown. Luster: Waxy to vitreous. Crystal Structure: Hexagonal (cryptocrystalline). Cleavage: None (conchoidal fracture). Specific Gravity: 2.58-2.64.

Hardness: 6
Color: Translucent orange to reddish-brown
Luster: Waxy to vitreous

Identified May 29, 2026More mineral →

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Physical properties

Formation & geological history

Forms in volcanic rocks (geodes or veins) as silica-rich groundwater precipitates in cavities. The color is derived from iron oxide (hematite) impurities throughout the chalcedony.

Uses & applications

Predominantly used for lapidary work, jewelry (beads, cabochons, signet rings), and metaphysical collecting. Historically used for cylinder seals and amulets.

Geological facts

Carnelian was highly prized in ancient Egypt and Rome; it was believed by ancient warriors to provide courage in battle. The name likely stems from the Latin word 'cornum', referring to the cornel cherry.

Field identification & locations

Identify by its waxy luster and translucent orange-red glow when backlit. Commonly found in Brazil, India, Uruguay, and Madagascar. In the field, look for smooth, rounded nodules with a dull exterior but colorful interior.

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