sedimentary

Weathered jasper-rich ironstone

Brecciated jasper/chert with iron oxides and hydroxides (SiO₂ with hematite, goethite, and limonite)

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque red-brown, gray, and yellow-brown with dull to slightly waxy luster and no visible cleavage. Fine-grained microcrystalline quartz gives it a dense, conchoidally fracturing texture; greenish surface patches likely represent copper minerals or secondary weathering products.

Identified August 14, 2026More sedimentary →

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Physical properties

Formation & geological history

Formed when silica-rich sediment or volcanic material was cemented and impregnated by iron-bearing fluids, then fractured and weathered near the surface. Its exact geological age cannot be determined from the photograph; such jasper formations range from Precambrian to younger rocks.

Uses & applications

Used as decorative stone, lapidary material, cabochons, carvings, and tumbled stone; ironstone may also be an iron ore, though this specimen appears primarily ornamental.

Geological facts

Jasper is an opaque variety of microcrystalline quartz, and its red coloration commonly comes from hematite. Green crusts can be misleading and should not automatically be identified as malachite without testing.

Field identification & locations

Identify by its very high hardness, dense feel, opaque coloration, and inability to scratch with a steel knife easily; a streak test may show white to reddish-brown. Common in hydrothermal, volcanic, and iron-rich sedimentary regions worldwide.