mineral
Tumbled yellow-brown jasper or chalcedony
Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony
AI-generated identification · may be incorrectMohs hardness 6.5–7; mustard-yellow to brown, opaque to slightly translucent, with a waxy to vitreous luster and no visible cleavage. The rounded shape indicates tumbling or natural water abrasion; specific gravity is about 2.6.
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Physical properties
Mohs hardness 6.5–7; mustard-yellow to brown, opaque to slightly translucent, with a waxy to vitreous luster and no visible cleavage. The rounded shape indicates tumbling or natural water abrasion; specific gravity is about 2.6.
Formation & geological history
Forms when silica-rich fluids fill cavities or replace rock, with iron oxides producing the yellow-brown coloration; commonly Cenozoic to older, depending on its host deposit. Exact age and locality cannot be determined from the photograph.
Uses & applications
Used as a lapidary stone for cabochons, beads, carvings, and decorative objects; attractive pieces are collectible but generally inexpensive.
Geological facts
Jasper is an opaque variety of chalcedony, while more translucent material is usually called chalcedony or carnelian. The specimen may also be yellow agate if internal banding is present but obscured by its finish.
Field identification & locations
Look for quartz-like hardness, a smooth waxy surface, absence of cleavage, and inability to scratch it with a steel blade; it should scratch ordinary glass. Common sources include Brazil, Madagascar, India, Mexico, and the western United States.
