mineral

Chert or chalcedony fragment

Microcrystalline quartz (SiO₂), likely ferruginous or jasper-like chalcedony

AI-generated identification · may be incorrect

Hardness about 6.5–7 Mohs; translucent cream to reddish-orange with a waxy luster and curved, conchoidal fracture. The thin, irregular fragment lacks visible crystals and may show iron-oxide staining; cleavage is absent.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms when silica-rich groundwater fills cavities or replaces sediments, commonly in volcanic or carbonate environments; iron staining develops during weathering. Its exact geological age cannot be determined from the image.

Uses & applications

Used for lapidary pieces, beads, tools, and ornamental stone; this small fragment has little commercial value unless it comes from a notable locality.

Geological facts

Chert and chalcedony can produce razor-sharp conchoidal edges when fractured. The reddish color commonly reflects hematite or other iron oxides rather than a separate red mineral.

Field identification & locations

Look for glassy or waxy luster, curved fracture surfaces, lack of cleavage, and inability to scratch it with a steel knife; quartz should scratch glass. Common worldwide, especially in sedimentary beds and volcanic regions.