metamorphic

Quartz-rich rock, likely weathered quartzite

Quartzite (predominantly crystalline SiO₂), possibly iron-stained quartz vein material

AI-generated identification · may be incorrect

Massive, pale gray to bluish translucent quartz with rusty red-brown iron-oxide staining; vitreous to dull luster and irregular fracture. Quartz hardness is Mohs 7, with no obvious cleavage; the specimen appears fine- to medium-grained and weakly foliated or brecciated.

Identified September 13, 2026More metamorphic →

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Physical properties

Formation & geological history

Likely formed when quartz-rich sandstone recrystallized during metamorphism, or as a silica-rich hydrothermal vein later fractured and oxidized. The precise age cannot be determined from the photograph; this type is geologically plausible in southern Brazil.

Uses & applications

Used as crushed aggregate, road stone, and decorative stone; attractive pieces may be collected or cut and polished, though this specimen appears relatively ordinary.

Geological facts

The red-orange coloration is probably hematite/goethite coating or cement rather than red quartz. Translucent edges and abundant hard, glassy grains support a quartz-dominant composition.

Field identification & locations

Test with a steel file or knife: genuine quartzite should resist scratching. A streak test should be white, and acid should not fizz unless carbonate minerals are present. Common in quartz-rich metamorphic terrains and hydrothermal zones; exact identification would benefit from a fresh surface, hardness test, and thin section.