mineral
Chalcedony
Silicon dioxide, SiO2
AI-generated identification · may be incorrectMohs hardness of 6.5 to 7, typically pale blue, gray, or white in color, waxy to vitreous luster, and microcrystalline structure with no cleavage.
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Physical properties
Mohs hardness of 6.5 to 7, typically pale blue, gray, or white in color, waxy to vitreous luster, and microcrystalline structure with no cleavage.
Formation & geological history
Forms in low-temperature hydrothermal environments or by precipitation from silica-rich groundwater within cavities of volcanic and sedimentary rocks.
Uses & applications
Used extensively in lapidary work for making ornamental carvings, beads, cabochons, and collector display specimens.
Geological facts
Botryoidal chalcedony displays a characteristic grape-like, rounded surface texture caused by concentric layers of microfibrous quartz growth.
Field identification & locations
Identify by its waxy luster, microcrystalline fracture, and characteristic botryoidal habit; commonly found in worldwide volcanic vesicle deposits.
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Other mineral specimens
Gneiss or Schist
Gneiss or Mica Schist with Garnet
Metamorphic
Sandstone (with potential mineral staining/concretions)
Arenite (SiO2 based)
sedimentary
Tumbled granite
Granite, a coarse-grained felsic intrusive igneous rock
igneous
Pegmatite with Tourmaline and Quartz
Igneous Pegmatite
igneous
Epidote
Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
igneous