metamorphic

Mica-rich metamorphic rock, likely biotite schist

Biotite–quartz schist; probable composition of quartz, biotite, feldspar, and minor sulfide or iron-oxide minerals

AI-generated identification · may be incorrect

Usually Mohs 2.5–7 depending on the mineral tested; dark brown to gray, with conspicuous flaky, reflective mica and rusty weathering. Strong schistosity, micaceous cleavage, and a granular crystalline texture are visible; exact identification is limited by the image.

Identified August 26, 2026More metamorphic →

Explore Mica-rich metamorphic rock, likely biotite schist 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: Mica-rich metamorphic rock, likely biotite schist
Scientific name: Biotite–quartz schist; probable composition of quartz, biotite, feldspar, and minor sulfide or iron-oxide minerals
Category: metamorphic
Identified: August 26, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$100+ for unusually large, colorful, or well-preserved display pieces.

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

Formed when mica- and quartz-bearing sedimentary or igneous rock was subjected to elevated temperature and directed pressure during regional metamorphism, commonly in Precambrian to Paleozoic mountain belts.

Uses & applications

Used locally as decorative stone, landscaping material, and educational specimens; attractive pieces may be collected, but it is rarely a major gemstone or construction stone.

Geological facts

The bright flashes are most likely cleavage surfaces of biotite or muscovite, while blue-gray grains may be quartz or feldspar reflecting light; rusty patches commonly represent oxidation of iron-bearing minerals.

Field identification & locations

Look for aligned mica flakes that peel or glitter, visible foliation, and hardness contrast between soft mica and harder quartz. Common in metamorphic terrains worldwide, including the Appalachians, Canadian Shield, and Scandinavian Shield.