igneous
Graphic Granite
Pegmatitic Feldspar and Quartz (Graphic Granite)
Hardness: 6-7 (Mohs); Color: Tan/pink base with dark smoky grey or black wedge-shaped patterns; Luster: Vitreous to pearly; Crystal structure: Monoclinic and Hexagonal; Cleavage: Perfect on feldspar; Specific gravity: 2.5-2.7
- Hardness
- 6-7 (Mohs)
- Luster
- Vitreous to pearly
Identified More igneous →
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Physical properties
Hardness: 6-7 (Mohs); Color: Tan/pink base with dark smoky grey or black wedge-shaped patterns; Luster: Vitreous to pearly; Crystal structure: Monoclinic and Hexagonal; Cleavage: Perfect on feldspar; Specific gravity: 2.5-2.7
Formation & geological history
Formed in late-stage cooling of granitic pegmatites. The specific texture occurs through parallel intergrowth of quartz and alkali feldspar, often at a specific eutectic point during crystallization.
Uses & applications
Decorative purposes, jewelry (cabochons), tiling, specimen collecting, and occasionally as a source of potassium feldspar for ceramics.
Geological facts
The name 'Graphic Granite' comes from the Greek word 'graphos', meaning writing, because the dark quartz crystals resemble ancient cuneiform or hieroglyphic script.
Field identification & locations
Identify by looking for dark, angular, rune-like markings embedded within a lighter-colored feldspar matrix. Commonly found in pegmatite fields in Canada, Russia, and the United States (Maine, California).
