gemstone

Red carnelian (polished chalcedony)

Carnelian, microcrystalline quartz (SiO₂), cryptocrystalline variety of chalcedony

AI-generated identification · may be incorrect

Smooth oval cabochon with translucent deep red-orange color and vitreous-to-waxy luster. Quartz hardness is about 6.5–7 Mohs; no visible cleavage, conchoidal fracture, trigonal microcrystalline structure, and specific gravity near 2.60–2.65.

Identified September 11, 2026More gemstone →

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Physical properties

Formation & geological history

Forms when iron-bearing silica or chalcedony is deposited in volcanic cavities and later oxidized, producing red coloration. It is commonly Cenozoic to older, with age dependent on the host rock; this cut stone cannot be dated visually.

Uses & applications

Used for cabochon jewelry, beads, seals, carvings, and ornamental objects. Common polished pieces generally have modest value.

Geological facts

Uniform red color and translucency are typical of carnelian; dyed chalcedony and red glass can look similar. Natural banding may be absent in high-quality material.

Field identification & locations

Common sources include India, Brazil, Uruguay, Madagascar, and parts of Pakistan; it is plausible near Karachi, though the photo alone cannot establish local origin. Check for glass bubbles, hardness, and conchoidal fracture; avoid scratch testing on finished jewelry.