mineral
Tumbled yellow jasper (probable)
Jasper, an opaque microcrystalline variety of quartz; chiefly SiO₂ with iron-oxide inclusions
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; mustard-yellow to brown mottling, opaque, waxy to vitreous luster, cryptocrystalline quartz with no obvious cleavage, and specific gravity near 2.6. The smooth rounded surface indicates tumbling and polishing.
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Physical properties
Hardness about 6.5–7 Mohs; mustard-yellow to brown mottling, opaque, waxy to vitreous luster, cryptocrystalline quartz with no obvious cleavage, and specific gravity near 2.6. The smooth rounded surface indicates tumbling and polishing.
Formation & geological history
Forms when silica-rich fluids replace or cement volcanic or sedimentary material, with iron oxides producing the yellow coloration. Deposits are generally ancient, though the specimen’s geological age cannot be determined visually.
Uses & applications
Used for cabochons, beads, carvings, ornamental objects, and inexpensive lapidary pieces; it has little industrial value compared with ordinary quartz.
Geological facts
Jasper is technically a rock rather than a single mineral, and color patterns often reflect trace iron, clay, and relic textures from the host rock.
Field identification & locations
Identify it by its opaque yellow color, mottled patterns, glassy/waxy polish, lack of cleavage, and ability to scratch ordinary glass. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
