mineral
Tumbled yellow jasper or iron-stained chert
Microcrystalline quartz (SiO₂), likely colored by iron oxides
AI-generated identification · may be incorrectOpaque mustard-yellow to tan, smoothly rounded and matte-to-waxy; hardness about 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, and specific gravity near 2.6. The dark internal marks may be iron-oxide or manganese-oxide inclusions.
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Physical properties
Opaque mustard-yellow to tan, smoothly rounded and matte-to-waxy; hardness about 6.5–7 Mohs, no visible cleavage, cryptocrystalline quartz structure, and specific gravity near 2.6. The dark internal marks may be iron-oxide or manganese-oxide inclusions.
Formation & geological history
Formed when silica-rich fluids replaced or cemented sediment, with iron staining producing the yellow color; its exact geological age cannot be determined from the image. The rounded shape indicates natural water wear or deliberate tumbling/polishing.
Uses & applications
Used as a lapidary stone for cabochons, beads, carvings, and decorative objects; generally not used structurally. It has modest jewelry and collecting value.
Geological facts
Jasper is an opaque variety of chalcedony/microcrystalline quartz, unlike transparent crystalline quartz. Similar yellow stones may include yellow chert, quartzite, or dyed material.
Field identification & locations
Test cautiously for glass-scratching hardness, inspect a fresh edge for a waxy cryptocrystalline texture, and avoid relying on color alone; common in river gravels and silica-rich volcanic or sedimentary terrains worldwide.
