igneous

Quartz-rich pegmatite or hydrothermal quartz specimen

Quartz (SiO₂) in a coarse felsic host, possibly pegmatitic granite with feldspar and mica

AI-generated identification · may be incorrect

Hardness: quartz 7 Mohs; crystals are colorless to smoky/gray with glassy luster and no cleavage, while the host appears granular and may contain feldspar and mica. Visible crystals are irregular to prismatic, with translucent quartz over a gray matrix.

Hardness: quartz 7 Mohs

Identified August 20, 2026More igneous →

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At a glance

Common name: Quartz-rich pegmatite or hydrothermal quartz specimen
Scientific name: Quartz (SiO₂) in a coarse felsic host, possibly pegmatitic granite with feldspar and mica
Category: igneous
Identified: August 20, 2026
Method: Standard

AI Estimated Value

Approximately $15–$75 for a common hand specimen; unusually large, well-crystallized, or locality-documented examples may sell for $100–$300.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Likely formed from silica-rich late-stage magma or hot hydrothermal fluids filling fractures and cavities, generally in Precambrian to Phanerozoic continental crust. The exact age and locality cannot be determined from the photograph.

Uses & applications

Quartz specimens are collected for display; quartz and feldspar are important in glass, ceramics, abrasives, and electronics. This rough specimen has modest decorative value rather than gemstone or construction value.

Geological facts

Quartz commonly shows conchoidal fracture and may fluoresce weakly depending on inclusions. The cloudy gray appearance can result from fluid inclusions, microscopic fractures, or associated feldspar and mica.

Field identification & locations

Look for glassy translucent grains, hardness sufficient to scratch ordinary glass, and quartz’s lack of cleavage; feldspar typically shows two cleavage directions. Common sources include Brazil, Madagascar, the United States, and China.