mineral

Chalcedony (Agate Pebble)

Silicon Dioxide (SiO2)

Hardness: 6.5-7 on Mohs scale; Color: translucent grey/white; Luster: waxy to vitreous; Crystal structure: cryptocrystalline (hexagonal); Cleavage: none; Specific Gravity: 2.6-2.64

Hardness: 6
Color: translucent grey/white
Luster: waxy to vitreous

Identified May 31, 2026More mineral →

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Physical properties

Hardness: 6.5-7 on Mohs scale; Color: translucent grey/white; Luster: waxy to vitreous; Crystal structure: cryptocrystalline (hexagonal); Cleavage: none; Specific Gravity: 2.6-2.64

Formation & geological history

Formed from the deposition of silica-rich groundwater in cavities of volcanic or sedimentary rocks. This specimen is water-worn, likely from a stream or beach environment.

Uses & applications

Commonly used for lapidary work, jewelry (cabochons), or as high-vibration healing stones in metaphysical practices; industrially used for mortar and pestles due to hardness.

Geological facts

Chalcedony is a cryptocrystalline form of silica, composed of very fine intergrowths of quartz and moganite. Translucent, bean-shaped pebbles like this are often referred to as 'moonlight agates' or 'sea glass agates' by beachcombers.

Field identification & locations

Identify by its waxy luster, translucency, and inability to be scratched by a steel knife. Commonly found in riverbeds, gravel pits, and coastal shorelines in volcanic regions.