Rock Identifier
Red jasper (Microcrystalline quartz (SiO₂), iron-oxide-rich chalcedony) — mineral
mineral

Red jasper

Microcrystalline quartz (SiO₂), iron-oxide-rich chalcedony

AI-generated identification · may be incorrect

Opaque brick-red to reddish-brown, with a dull to waxy luster and possible dark inclusions; hardness about 6.5–7 Mohs, no cleavage, conchoidal fracture, and specific gravity near 2.6. The specimen appears raw and freshly chipped.

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Physical properties

Opaque brick-red to reddish-brown, with a dull to waxy luster and possible dark inclusions; hardness about 6.5–7 Mohs, no cleavage, conchoidal fracture, and specific gravity near 2.6. The specimen appears raw and freshly chipped.

Formation & geological history

Forms when silica-rich fluids fill cavities or replace sediments and volcanic rocks, with hematite or other iron oxides producing the red color. It commonly formed in Precambrian to younger hydrothermal and sedimentary environments.

Uses & applications

Used for cabochons, beads, carvings, ornamental objects, and lapidary practice; historically used for tools and decorative stone. It has limited industrial value compared with quartz aggregates.

Geological facts

Jasper is an opaque variety of chalcedony, unlike transparent gem-quality quartz. Color intensity and patterns depend mainly on iron-oxide content and impurities.

Field identification & locations

Identify it by its opaque red color, substantial weight, hardness, and inability to scratch with a steel knife easily; it should not fizz in dilute hydrochloric acid. Common sources include India, Brazil, Madagascar, the United States, and Australia.