Rock Identifier
Polished brecciated jasper (Jasper, microcrystalline quartz (SiO₂), with iron-oxide and pale silica-rich fragments) — mineral
mineral

Polished brecciated jasper

Jasper, microcrystalline quartz (SiO₂), with iron-oxide and pale silica-rich fragments

AI-generated identification · may be incorrect

Typically hardness 6.5–7 Mohs, opaque, with a glassy-to-waxy luster and irregular breccia-like patterning. The dark reddish-brown matrix reflects iron oxides; the pale patches are likely quartz or altered host rock.

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Physical properties

Typically hardness 6.5–7 Mohs, opaque, with a glassy-to-waxy luster and irregular breccia-like patterning. The dark reddish-brown matrix reflects iron oxides; the pale patches are likely quartz or altered host rock.

Formation & geological history

Forms when silica-rich fluids cement and replace fragmented volcanic or sedimentary rock, commonly during hydrothermal alteration. Individual jasper bodies range widely in age, from Precambrian to Cenozoic.

Uses & applications

Used for tumbled stones, cabochons, carvings, decorative objects, and lapidary collections; unsuitable as a major construction stone in this small polished form.

Geological facts

Jasper is a variety of opaque chalcedony or microcrystalline quartz, and “brecciated” describes its angular fragments cemented together. Exact variety and locality generally require visual comparison or laboratory testing.

Field identification & locations

Identify it by its opaque red-brown color, angular contrasting fragments, quartz-like hardness, and absence of cleavage; it should resist scratching by a steel blade. Common sources include India, Madagascar, Brazil, Mexico, and the western United States.