Breccia

Breccia is distinguished from conglomerate by its angular clasts.

Rock group Sedimentary
Origin Clastic/detrital
Particle size (Wentworth) >2 mm

Breccia in Hand Sample

Volcaniclastic breccia from Mount St. Helens
Volcaniclastic breccia from the Gallatin Range, Montana
Fault breccia from the Hebgen Lake Fault
Landslide breccia from the Crazy Cat landslide in El Paso, Texas
Brecciated quartzite from the Cambrian-aged Antietam Formation
Plate breccia
Intrusion breccia
Breccia in basalt
Serpentinite breccia from the North Anatolian Fault

Breccia in Thin Section

Volcanic breccia, plane polars
Volcanic breccia, crossed polars
Marble breccia, plane polars
Marble breccia, crossed polars
Lunar sample 65015, plane polars
Lunar sample 65015, crossed polars

Lunar sample 65015 is impact breccia collected from the moon by the Apollo 16 astronauts! It was imaged by, and is used with the permission of, Paul Karabinos. NASA offers a brief but full and useful description here. The Lunar and Planetary Institute hosts dozens of photos, including the hand sample from which it was cut, chipping diagrams, and photos documenting every cut of the sample.

Volcanic breccia, plane polars

Volcanic breccia, plane polars

Volcanic breccia in plane polarized light. Magnification: 40x Click here for crossed polars: https://youtu.be/xIsqSRvsJnw Click here to explore this slide in…

Volcanic breccia, crossed polars

Volcanic breccia, crossed polars

Volcanic breccia in cross polarized light. Magnification: 40x Click here for plane polars: Click here to explore this slide in plane polars: https://viewer.g…

Marble, plane polars

Marble breccia, plane polars

Marble breccia in plane polarized light. Magnification: 40x Click here for crossed polars: https://youtu.be/urh9GU95Ya8 Click here to explore this slide in p…

Marble breccia, crossed polars

Marble breccia, crossed polars

Marble breccia in cross polarized light. Magnification: 40x Click here for plane polars: https://youtu.be/Fh79XjMp26g Click here to explore this slide in pla…