metamorphic
Polished orbicular jasper (likely leopard-skin or brecciated jasper)
Microcrystalline quartz (SiO₂), with iron-oxide and other mineral inclusions; exact variety cannot be confirmed from the photo
AI-generated identification · may be incorrectOpaque, polished dark gray-black stone with scattered pale and reddish spots; quartz hardness about 6.5–7 Mohs, vitreous to waxy luster, no visible cleavage, microcrystalline structure. The sphere appears roughly 4 cm across.
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Physical properties
Opaque, polished dark gray-black stone with scattered pale and reddish spots; quartz hardness about 6.5–7 Mohs, vitreous to waxy luster, no visible cleavage, microcrystalline structure. The sphere appears roughly 4 cm across.
Formation & geological history
Silica-rich fluids and volcanic or sedimentary processes formed the quartz-rich material; iron oxides and other minerals created the contrasting spots. Jasper deposits formed in many geological periods, so age depends on source.
Uses & applications
Used for decorative spheres, carvings, jewelry, and mineral collecting.
Geological facts
Jasper is an opaque variety of chalcedony, and its colors and patterns arise from mineral impurities. Polishing can make its fine-grained patterns especially visible.
Field identification & locations
Look for an opaque, dense stone with a smooth polish and irregular mineral spots; a scratch test or laboratory analysis is needed to distinguish jasper from other patterned stones. Jasper is found worldwide, including India, Madagascar, Brazil, and the United States.
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