mineral
Likely tumbled yellow jasper or iron-rich chert
Microcrystalline quartz (SiO₂), colored by iron oxides
AI-generated identification · may be incorrectOpaque mustard-yellow to brown, waxy to dull luster, massive microcrystalline structure, no visible cleavage, conchoidal fracture; hardness about 6.5–7 Mohs and specific gravity about 2.6.
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Physical properties
Opaque mustard-yellow to brown, waxy to dull luster, massive microcrystalline structure, no visible cleavage, conchoidal fracture; hardness about 6.5–7 Mohs and specific gravity about 2.6.
Formation & geological history
Forms when silica-rich fluids replace or cement sediment, with iron oxides producing the yellow color; typically associated with sedimentary or volcanic environments, ranging from Precambrian to younger deposits.
Uses & applications
Used as an ornamental and lapidary stone for cabochons, beads, carvings, and tumbled specimens; usually not important for construction.
Geological facts
Jasper is technically a variety of opaque, impure chalcedony or chert. The rounded shape and smooth surface indicate tumbling or natural abrasion, while the granular interior is consistent with jasper rather than a transparent crystal.
Field identification & locations
Identify by its opaque body, fine texture, waxy surface, lack of cleavage, and resistance to scratching; a steel file should generally not scratch it. Common sources include India, Madagascar, Brazil, Australia, and the western United States.
