mineral
Banded agate (agate nodule slice)
Agate, a banded variety of microcrystalline quartz; SiO₂
AI-generated identification · may be incorrectHardness 6.5–7 Mohs; gray, white, and charcoal concentric bands with a vitreous to waxy luster. Trigonal quartz composed of microscopic crystals; no distinct cleavage, conchoidal fracture, specific gravity about 2.6.
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Physical properties
Hardness 6.5–7 Mohs; gray, white, and charcoal concentric bands with a vitreous to waxy luster. Trigonal quartz composed of microscopic crystals; no distinct cleavage, conchoidal fracture, specific gravity about 2.6.
Formation & geological history
Silica-rich fluids deposited successive chalcedony layers in cavities, commonly in volcanic rock; the specimen’s precise age and source cannot be determined from the image.
Uses & applications
Used for jewelry, ornaments, cabochons, and decorative slabs; also collected for its distinctive natural banding.
Geological facts
Agate is a variety of chalcedony, and its concentric bands can preserve a record of changing conditions during mineral deposition.
Field identification & locations
Identify by its fine, curved or concentric bands and quartz-like hardness; agates occur worldwide, including in volcanic regions and stream gravels. Image-based identification cannot establish locality or treatment.
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