Rock Identifier
Tumbled brecciated jasper (Microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions) — gemstone
gemstone

Tumbled brecciated jasper

Microcrystalline quartz (SiO₂) with iron-oxide and other mineral inclusions

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, reddish-brown with gray-white angular patches, and a dull to waxy luster; no visible cleavage and cryptocrystalline structure. The rounded shape indicates tumbling or natural abrasion.

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Physical properties

Typically hardness 6.5–7 Mohs, opaque, reddish-brown with gray-white angular patches, and a dull to waxy luster; no visible cleavage and cryptocrystalline structure. The rounded shape indicates tumbling or natural abrasion.

Formation & geological history

Forms when silica-rich fluids replace or cement earlier rock fragments, commonly with hematite/goethite producing red-brown coloration; specimens may range from Paleozoic to younger depending on locality. Exact identification and age require testing or provenance.

Uses & applications

Used for cabochons, beads, carvings, tumbled stones, and small decorative objects; generally not used structurally. Common material has modest jewelry and collecting value.

Geological facts

“Jasper” is a broad lapidary term for opaque, impure microcrystalline quartz rather than one single mineral species. Brecciation creates the angular contrasting pattern visible in the pebble.

Field identification & locations

Commonly found in volcanic and hydrothermal terrains, including Oregon, Idaho, Arizona, Madagascar, India, and Australia. Confirm with a 6.5–7 Mohs scratch test, absence of glassy translucence, and magnification showing irregular quartz-rich texture.