mineral
Polished dendritic agate or jasper
Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions
AI-generated identification · may be incorrectHardness about 6.5–7 Mohs; cream to pale yellow, translucent, with brown-red branching or cloudlike iron staining; waxy to glassy luster and no visible cleavage. Its rounded, polished form is human processed.
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Physical properties
Hardness about 6.5–7 Mohs; cream to pale yellow, translucent, with brown-red branching or cloudlike iron staining; waxy to glassy luster and no visible cleavage. Its rounded, polished form is human processed.
Formation & geological history
Silica-rich groundwater deposited chalcedony in cavities or fractures, while iron oxides produced the brown inclusions; these commonly formed in volcanic rocks during the Cenozoic or older geological episodes. Exact locality and age cannot be determined from the photograph.
Uses & applications
Used as a cabochon, tumbled stone, carving, or collector specimen; durable enough for jewelry and ornamental objects, but not typically used as construction aggregate when sold as a gem material.
Geological facts
The pattern may be dendritic agate if the markings are branching, or iron-stained jasper if the stone is more opaque and massive. Polishing enhances its translucency and color contrast.
Field identification & locations
Identify by its quartz-like hardness, smooth conchoidal fracture if tested, waxy/glassy polish, and lack of cleavage; avoid destructive tests on a finished cabochon. Similar material occurs worldwide, notably India, Brazil, Madagascar, Mexico, and the United States.
