igneous

Quartz-rich pegmatite (likely feldspar–quartz–mica rock)

Granitic pegmatite; chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), and mica

AI-generated identification · may be incorrect

Coarse, irregular interlocking crystals; white to pink/tan feldspar, translucent gray-white quartz, and possible pale mica. Quartz hardness is 7, feldspar 6–6.5, mica 2–3; generally vitreous to pearly luster and no overall cleavage.

Identified September 9, 2026More igneous →

Explore Quartz-rich pegmatite (likely feldspar–quartz–mica rock) in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

At a glance

Common name: Quartz-rich pegmatite (likely feldspar–quartz–mica rock)
Scientific name: Granitic pegmatite; chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), and mica
Category: igneous
Identified: September 9, 2026
Method: Standard

AI Estimated Value

About $10–$50 for a common hand specimen; $50–$200+ if it contains large, attractive crystals or rare associated minerals.

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

A very slow-cooling, volatile-rich igneous melt formed in the final stages of granite intrusion, producing exceptionally large crystals. Most pegmatites are Precambrian to Phanerozoic, depending on locality.

Uses & applications

Used as an ornamental and collector specimen; pegmatites can supply feldspar, quartz, mica, lithium, tantalum, and gemstones such as tourmaline and beryl.

Geological facts

The specimen’s rusty orange coloration likely reflects iron staining or altered feldspar rather than a distinct mineral. Exact identification requires a close examination, hardness tests, and ideally a thin section or chemical analysis.

Field identification & locations

Common in granite terrains worldwide, including Maine, California, Brazil, Madagascar, and Scandinavia. Look for very coarse crystals, graphic quartz–feldspar textures, and mica flakes; avoid assuming every pale massive piece is pegmatite.