gemstone

Polished banded agate (likely carnelian/black agate)

Microcrystalline quartz, SiO₂ (chalcedony/agate)

AI-generated identification · may be incorrect

Hardness 6.5–7 Mohs; glossy vitreous to waxy luster; opaque to translucent, with dark brown-black and reddish-orange curved bands. Quartz has no visible cleavage and conchoidal fracture; specific gravity is about 2.60–2.65.

Identified September 11, 2026More gemstone →

Explore Polished banded agate (likely carnelian/black agate) in the encyclopedia →

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Physical properties

Formation & geological history

Agate forms when silica-rich groundwater fills cavities in volcanic rock, depositing successive chalcedony layers. The polished cabochon shown is human-shaped; the specimen’s geological age depends on its host rock, commonly Cenozoic or older.

Uses & applications

Used for cabochons, beads, carvings, ornaments, and lapidary items; durable and inexpensive compared with precious gemstones.

Geological facts

The dark bands may be iron-oxide-rich layers, while red-orange areas resemble carnelian. A smooth polish and regular curvature indicate a cut cabochon rather than a naturally weathered pebble.

Field identification & locations

Identify by its curved internal banding, quartz-like hardness, and glassy polish; it should scratch ordinary glass but not be scratched by a steel knife. Agates are widespread worldwide, including sedimentary and volcanic terrains around the Karachi–Sindh region, though exact locality cannot be confirmed visually.