sedimentary
Breccia
Breccia
Hardness: 6-7 (clasts), variable matrix. Color: Tan/brown matrix with dark grey/black angular clasts. Luster: Dull to earthy. Structure: Clastic, featuring sharp-edged gravel-sized particles. Cleavage: None.
- Hardness
- 6-7 (clasts), variable matrix
- Color
- Tan/brown matrix with dark grey/black angular clasts
- Luster
- Dull to earthy
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Physical properties
Hardness: 6-7 (clasts), variable matrix. Color: Tan/brown matrix with dark grey/black angular clasts. Luster: Dull to earthy. Structure: Clastic, featuring sharp-edged gravel-sized particles. Cleavage: None.
Formation & geological history
Formed by the accumulation of angular rock fragments cemented together by mineral-rich fine-grained matrix. Often occurs in fault zones, landslide deposits, or as collapse features. No specific age; forms through geological time.
Uses & applications
Primarily used as road base, architectural stone, and decorative gravel. Polished specimens are used for tabletops or jewelry in lapidary work.
Geological facts
Unlike Conglomerate, which has rounded edges from water travel, Breccia's angular fragments indicate that the source material was moved only a short distance from where it broke.
Field identification & locations
Identify by the prominent angular (sharp-edged) rock fragments larger than 2mm. Commonly found at the base of cliffs (talus) or in tectonic fault boundaries. Collectors look for high color contrast between fragments and matrix.
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