mineral

Carnelian (Tumbled)

SiO2 (Silicon Dioxide / Chalcedony)

Hardness: 6.5-7 on Mohs scale; Color: Orange, reddish-orange, peach; Luster: Waxy to vitreous when polished; Crystal Structure: Trigonal (microcrystalline/cryptocrystalline); Cleavage: None, exhibits conchoidal fracture; Specific Gravity: 2.58-2.64

Hardness: 6
Color: Orange, reddish-orange, peach
Luster: Waxy to vitreous when polished

Identified July 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the deposition of silica from low-temperature solutions in cavities of other rocks, particularly volcanic rocks like basalt. Iron oxide impurities give it its distinct reddish-orange coloration.

Uses & applications

Widely used in lapidary arts, jewelry making (beads, cabochons, carved intaglios), tumbling, and decorative crystal collections.

Geological facts

Carnelian has been used in jewelry for over 4,500 years, notably in ancient Egyptian, Roman, and Sumerian cultures for amulets and signet rings.

Field identification & locations

Identified by its warm orange-red translucent appearance, smooth polished finish from tumbling, and lack of visible crystalline faces. Commonly found in Brazil, India, Madagascar, and Uruguay.

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