mineral

Grey Agate (Tumbled)

Silicon Dioxide (SiO2)

Hardness: 6.5–7 on Mohs scale; Color: Translucent grey with subtle banding; Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.58–2.64

Hardness: 6
Color: Translucent grey with subtle banding
Luster: Vitreous to waxy

Identified April 16, 2026More mineral →

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Physical properties

Hardness: 6.5–7 on Mohs scale; Color: Translucent grey with subtle banding; Luster: Vitreous to waxy; Crystal structure: Trigonal (cryptocrystalline); Cleavage: None; Specific Gravity: 2.58–2.64

Formation & geological history

Formed in cavities of volcanic rocks or ancient lavas. As silica-rich water percolates through voids, microcrystalline quartz layers deposit over time. Most agates are hundreds of millions of years old.

Uses & applications

Commonly used in lapidary arts, jewelry (beads, cabochons), meditation stones, and industrial mortars/pestles due to its hardness.

Geological facts

Agate is named after the Achates River in Sicily where they were first found. Grey agate is often associated with calmness and emotional stability in metaphysical circles.

Field identification & locations

Identify by its waxy texture and translucent nature when held to light. Look for concentric or parallel banding patterns. Tumbled specimens like this one are smoothed in a rock tumbler.