igneous / metamorphic

Granite and granitic gneiss outcrop

Granite: quartz–feldspar–mica rock; gneiss: banded quartzofeldspathic metamorphic rock

AI-generated identification · may be incorrect

Coarse-grained, gray to pink rocks with visible quartz, feldspar, and dark biotite or hornblende; typically Mohs 6–7, vitreous to dull luster, massive in granite and foliated or banded in gneiss, with little cleavage as a whole rock.

Identified August 24, 2026More igneous / metamorphic →

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At a glance

Common name: Granite and granitic gneiss outcrop
Scientific name: Granite: quartz–feldspar–mica rock; gneiss: banded quartzofeldspathic metamorphic rock
Category: igneous / metamorphic
Identified: August 24, 2026
Method: Standard

AI Estimated Value

$5–$30 for common hand specimens; $30–$200 for attractive polished or unusually patterned pieces; outcrop rock has essentially no collector value.

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

Granite crystallized slowly from silica-rich magma deep underground, while adjacent gneiss formed by high-temperature metamorphism of older crust; these rocks commonly represent Precambrian to Mesozoic continental bedrock and were later exposed by uplift and erosion.

Uses & applications

Used as dimension stone, building stone, countertops, monuments, aggregate, and riprap; attractive polished pieces are collected but are generally not jewelry gemstones.

Geological facts

The image shows a natural rocky stream gorge and waterfall, with rounded cobbles produced by weathering and abrasion. Darker layers or banding may indicate gneiss, while lighter coarse-grained surfaces are likely granite.

Field identification & locations

Identify quartz by its glassy appearance, feldspar by its blocky pink or white grains, and mica or hornblende by dark flakes or crystals; common in continental mountain belts worldwide, including the Sierra Nevada and Appalachian regions.