Copper-bearing Mica Schist

Physical Properties

Hardness: 2.5-4 (Schist matrix), 2.5-3 (Copper); Color: Silvery-grey to dark grey with reddish-metallic flecks; Luster: Pearly to metallic; Structure: Foliated/Schistose; Cleavage: Perfect basal on mica grains.

Formation & Geological History

Formed through the regional metamorphism of clay-rich sedimentary rocks (like shale) under medium to high pressure and temperature. The copper inclusions typically result from hydrothermal fluids depositing minerals in the rock's fractures or foliation planes.

Uses & Applications

Used primarily as decorative stone, in landscaping, or for geological study. If copper content is high enough, it can be an indicator of larger ore bodies for mining.

Geological Facts

Schist is characterized by its large, platy grains (mica) which are visible to the naked eye. The term 'schist' is derived from the Greek word 'schizein', meaning 'to split', referring to how the rock easily breaks along foliation planes.

Field Identification & Locations

Identify in the field by its distinct layered (foliated) appearance and the 'glittery' shine of mica crystals. Look for metallic orange/red flecks that indicate copper presence. Common in regions with a history of mountain-building (Orogeny).

Identified on: 4/14/2026

Mode: Standard