Quartz with Mica inclusions (likely Schist or Gneiss host)

Physical Properties

Hardness: 7 (quartz part) to 2.5 (mica part); Color: Yellowish-tan and dark grey/black; Luster: Vitreous to pearly; Crystal structure: Trigonal/Hexagonal; Cleavage: None (quartz) to perfect basal (mica).

Formation & Geological History

Formed through high-grade regional metamorphism of clay-rich sedimentary rocks or igneous granites. The quartz often segregates into bands or pockets during recrystallization under intense heat and pressure.

Uses & Applications

Common industrial use includes abrasives and glass making; as a specimen, it is mostly for hobbyist collecting or education.

Geological Facts

Quartz is the most abundant mineral in Earth's continental crust. When found with dark mica (biotite) or silvery mica (muscovite), it tells a story of the intense geological pressure the rock endured deep underground.

Field Identification & Locations

Identify by checking hardness (quartz will scratch glass) and looking for the characteristic 'flaky' or 'platey' texture of the dark mineral inclusions. Frequently found in riverbeds or mountainous metamorphic terranes.

Identified on: 5/14/2026

Mode: Standard