Rock Identifier
Iron-rich jasper or hematite-bearing chert (Microcrystalline quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))) — sedimentary
sedimentary

Iron-rich jasper or hematite-bearing chert

Microcrystalline quartz (SiO₂) with hematite/goethite (Fe₂O₃/FeO(OH))

AI-generated identification · may be incorrect

Hardness approximately 6.5–7 for the quartz matrix; earthy red-brown to purple coloration, dull to waxy luster, massive microcrystalline structure, and no obvious cleavage. The rusty metallic patches likely reflect iron oxides; a reddish-brown streak would support hematite-rich material.

Identified More sedimentary
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Physical properties

Hardness approximately 6.5–7 for the quartz matrix; earthy red-brown to purple coloration, dull to waxy luster, massive microcrystalline structure, and no obvious cleavage. The rusty metallic patches likely reflect iron oxides; a reddish-brown streak would support hematite-rich material.

Formation & geological history

Likely formed when silica-rich sediment or chert became impregnated with iron oxides during groundwater alteration; such deposits range from Precambrian banded iron formations to much younger weathering zones. Exact age and identification require locality and testing.

Uses & applications

Used as decorative stone, lapidary material, cabochons, carvings, and inexpensive specimen material; iron-rich varieties may have limited mineral-collecting interest.

Geological facts

Jasper is an opaque variety of chalcedony or microcrystalline quartz, and its colors commonly come from hematite, goethite, or other iron minerals. The pictured specimen appears rough and naturally fractured rather than polished.

Field identification & locations

Look for a quartz-like hardness, opaque red-brown body, and possible red-brown streak; it should scratch glass but not be scratched by a steel knife. Common in iron-rich sedimentary terrains and volcanic-hosted silica deposits.