mineral

Chalcedony Agate Geode / Nodule

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Hardness: 6.5-7 Mohs scale. Color: Translucent grayish-white, light blue to pale pinkish tones. Luster: Waxy to vitreous. Crystal Structure: Trigonal (microcrystalline/cryptocrystalline). Specific Gravity: 2.58-2.64. No cleavage, conchoidal fracture.

Hardness: 6
Color: Translucent grayish-white, light blue to pale pinkish tones
Luster: Waxy to vitreous

Identified July 26, 2026More mineral →

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Physical properties

Formation & geological history

Formed via low-temperature precipitation of silica-rich fluids within volcanic cavity gas bubbles (vesicles) or sedimentary limestone cavities over millions of years.

Uses & applications

Used extensively in gemstone carving, lapidary arts, jewelry (cabochons and beads), and as collectible display mineral specimens.

Geological facts

Agates and chalcedony nodules often feature botryoidal (grape-like) or banding patterns formed as layer upon layer of microcrystalline quartz deposited inside a hollow cavity.

Field identification & locations

Identified by its waxy luster, conchoidal fracture, chalcedonic translucent banding, and extreme hardness (scratches glass). Commonly found in volcanic regions, alluvial gravel beds, and desert floor deflation surfaces globally.

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