mineral

Agate Slices and Clear Quartz Points

Agate (SiO2 Chalcedony) and Clear Quartz (SiO2 Crystalline)

Hardness: 7 (Mohs scale); Color: Brown/tan banded (agate) and colorless transparent (quartz); Luster: Vitreous to waxy; Crystal structure: Trigonal/Microcrystalline; Cleavage: None/Conchoidal fracture; Specific gravity: 2.6-2.65.

Hardness: 7 (Mohs scale)
Color: Brown/tan banded (agate) and colorless transparent (quartz)
Luster: Vitreous to waxy

Identified March 16, 2026More mineral →

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Physical properties

Formation & geological history

Formed from silica-rich groundwater filling cavities (vugs) in volcanic or sedimentary rocks. The agate slices formed through rhythmic precipitation of silica layers, while the quartz points grew as macro-crystals in larger voids. These can date back millions of years depending on the host rock formation.

Uses & applications

Used primarily for decorative home decor (wind chimes, coasters), lapidary arts, jewelry, and metaphysical collecting. Industrially, high-quality quartz is used in electronics and optics.

Geological facts

Agate is named after the Achates River in Sicily. The banding in agate is caused by the varying impurities and rate of deposition of the silica. The 'points' shown are natural hexagonal prisms of quartz, though often polished for retail.

Field identification & locations

Identify in the field by checking for waxy luster, conchoidal fracture (glass-like chips), and the ability to scratch glass. Agates are common in river beds and beaches in volcanic regions (e.g., Brazil, Oregon, Lake Superior); Quartz is globally ubiquitous.

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