Breccia identification and geology

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• Conglomerate
• Clast
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Sources, scope & corrections

These authoritative resources support category-level nomenclature, terminology, identification methods, and safety. When a specimen-specific safety warning appears, the public-health source listed here directly supports that precaution. They are not line-by-line citations for every other property on this entry, and natural specimens vary.

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GeoMiner

Last updated

2026-03-30T15:19:41.970235+00:00

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Published; not independently peer-reviewed

• USGS Thesaurus — U.S. Geological Survey. Controlled earth-science terminology used to describe USGS information resources.
• Glossary of Geologic Terms — U.S. National Park Service. Geologic definitions prepared by the NPS Geologic Resources Inventory.

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Common questions

What does Breccia mean in geology?

A coarse-grained rock composed of angular fragments clasts greater than 2 mm in diameter cemented in a finer-grained matrix. Unlike conglomerate, which has rounded clasts, breccia's angular fragments indicate minimal transport and abrasion. Breccias can be sedimentary talus, fault , volcanic pyroclastic , or tectonic fault breccia in origin, and the genesis is important for interpretation.

What is an example of Breccia?

Fault breccia along the San Andreas Fault zone consists of angular fragments of crushed granite and schist cemented by secondary silica and calcite, recording brittle deformation along the fault plane.

Which earth-science field uses the term Breccia?

Breccia is used in petrology.

Which terms are related to Breccia?

Related terms in this reference are Conglomerate, Clast, Fault breccia, Pyroclastic.