Mineral
Agate
Chalcedony (Microcrystalline Quartz) - SiO2
AI-generated identification · may be incorrectHardness of 6.5-7 on the Mohs scale. Colors vary widely, but this specimen is pale grey/white with translucent to opaque banding. Waxy luster. Microcrystalline structure with no cleavage.
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Physical properties
Hardness of 6.5-7 on the Mohs scale. Colors vary widely, but this specimen is pale grey/white with translucent to opaque banding. Waxy luster. Microcrystalline structure with no cleavage.
Formation & geological history
Forms primarily in volcanic and metamorphic rocks from silica-rich groundwater filling cavities or veins. Deposition occurs in layers, creating the characteristic banding.
Uses & applications
Commonly used in jewelry (as cabochons or pendants, note the drilled hole in this piece), decorative items, and lapidary arts. Historically used for hardstone carving.
Geological facts
Agate was named by Theophrastus, a Greek philosopher and naturalist, who discovered the stone along the shoreline of the river Achates in Sicily.
Field identification & locations
Identify by its waxy luster, hardness (scratches glass), and characteristic banded or moss-like inclusions. Found worldwide, with notable deposits in Brazil, Uruguay, and the USA.
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