mineral

Polished brown jasper pebble with a quartz vein

Jasper (microcrystalline quartz, SiO₂), traversed by quartz or chalcedony

AI-generated identification · may be incorrect

Opaque reddish-brown to chocolate-brown, smooth polished surface, dull to vitreous luster, and hardness about 6.5–7 Mohs; the pale vein is harder quartz. No visible cleavage; jasper is cryptocrystalline quartz with very fine grains.

Identified September 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed when silica-rich fluids filled fractures in iron-rich volcanic or sedimentary material, later silicifying the host rock; the exact geological age cannot be determined from the photograph. Common in hydrothermal and volcanic terrains.

Uses & applications

Used for cabochons, beads, carvings, lapidary pieces, and decorative objects; not generally used as a major construction stone in this small form.

Geological facts

The contrasting pale line is a mineral-filled fracture, making this a brecciated or veined jasper appearance rather than a uniform jasper. Brown coloration commonly reflects iron oxides and hydroxides.

Field identification & locations

Identify it by its opaque earthy color, very fine texture, glassy polish, and inability to scratch with a steel knife easily; quartz vein material may show a lighter translucent edge. Found worldwide, including India, Madagascar, Brazil, Australia, and the western United States.