sedimentary

Iron-stained quartz-rich stone (probable jasper or chert)

Microcrystalline quartz (SiO₂), likely ferruginous jasper/chert

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; opaque brown, gray, and yellow with earthy to dull vitreous luster. Quartz grains are cryptocrystalline, with no obvious cleavage and irregular fracture; iron oxides produce the rusty colors.

Identified September 16, 2026More sedimentary →

Explore Iron-stained quartz-rich stone (probable jasper or chert) in the encyclopedia →

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Physical properties

Formation & geological history

Likely formed by silica-rich replacement or cementation of sediment, followed by iron-oxide staining during weathering. Precise age and locality cannot be determined from the photograph.

Uses & applications

Used as a decorative stone, lapidary material, and occasional cabochon or tumbled stone; low-grade pieces have little industrial value.

Geological facts

Jasper and chert can look very similar visually; a fresh edge showing a smooth, waxy fracture is characteristic of microcrystalline quartz.

Field identification & locations

Common in sedimentary terrains, gravel deposits, and hydrothermal zones worldwide. Field identification requires a glass-scratch test, streak, and preferably a fresh broken surface; the image alone cannot exclude weathered quartzite or another siliceous rock.