metamorphic

Epidote–garnet skarn (probable copper-bearing alteration rock)

Calc-silicate skarn; likely epidote, garnet, chlorite, quartz/calcite, and iron oxides/sulfides

AI-generated identification · may be incorrect

Hardness commonly 6–7 (garnet/epidote), locally softer where chlorite or calcite occurs. The specimen is mottled dark red-brown, olive-green, yellow-green, and black, with a wet vitreous-to-waxy luster; granular, massive texture and no obvious cleavage.

Identified September 15, 2026More metamorphic →

Explore Epidote–garnet skarn (probable copper-bearing alteration 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: Epidote–garnet skarn (probable copper-bearing alteration rock)
Scientific name: Calc-silicate skarn; likely epidote, garnet, chlorite, quartz/calcite, and iron oxides/sulfides
Category: metamorphic
Identified: September 15, 2026
Method: Standard

AI Estimated Value

$5–$30 for a common rough piece; approximately $30–$100+ if unusually colorful, mineralized, or polished.

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

Skarn forms when hot, chemically reactive fluids from an intrusion alter carbonate or volcanic rocks, commonly during the Mesozoic or younger. The red-brown areas may be garnet or iron-rich alteration, while green zones are likely epidote/chlorite.

Uses & applications

Primarily a field and lapidary specimen; attractive pieces may be polished. Skarn can host economically important copper, gold, tungsten, iron, and molybdenum deposits, but this photograph alone does not establish ore grade.

Geological facts

The vivid color mixture and apparent fine-grained replacement texture are characteristic of hydrothermal alteration rather than a single mineral. Near 49.3°N, 124.2°W, Vancouver Island–Coast Range metamorphic and hydrothermal rocks make this identification geologically plausible.

Field identification & locations

Look for epidote’s pistachio-green color, garnet’s red-brown granular patches, and hardness sufficient to scratch glass. A streak test, acid test on pale carbonate veins, magnet test, and fresh-break examination would improve confidence; visible metallic sulfides could indicate copper mineralization.