mineral

Tumbled carnelian (orange chalcedony)

Carnelian, a microcrystalline variety of quartz; silicon dioxide (SiO₂) colored mainly by iron oxides

AI-generated identification · may be incorrect

Mohs hardness 6.5–7; vivid orange to reddish-orange, translucent to opaque, and typically waxy to vitreous in luster. It has cryptocrystalline quartz structure, no visible cleavage, conchoidal fracture, and specific gravity near 2.60–2.65.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities and fractures in volcanic rocks, with iron producing the orange-red color; some material is heat-treated to intensify color. Deposits range from relatively young volcanic settings to ancient volcanic and sedimentary rocks.

Uses & applications

Used for beads, cabochons, carvings, and inexpensive jewelry; historically used for seals and ornamental objects. Tumbled pieces are mainly sold as decorative or metaphysical specimens.

Geological facts

Carnelian is a variety of chalcedony, closely related to agate. Its color may darken or redden with heating or prolonged exposure to sunlight.

Field identification & locations

Identify by its orange color, smooth waxy surface, translucency, lack of cleavage, and ability to scratch glass; dyed glass or plastic may show bubbles or uneven artificial color. Common sources include India, Brazil, Uruguay, Madagascar, and the United States.