Identification guide · Sedimentary Rocks
How to Identify Breccia
Breccia is variable in color with a varies luster and is opaque. It has a Mohs hardness of 3.5. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Its streak is variable; test individual minerals. It is most often confused with Calcite, Conglomerate, and Travertine; the tests below separate them.
Breccia identification checklist
| Luster | Varies | Compare a fresh surface with glass and metal; this luster is softer than either. |
|---|---|---|
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 3.5 | A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. |
| Streak | Variable; test individual minerals | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Variable by mineral grains | |
| Fracture | Uneven to granular | |
| Specific gravity | 2.4 | Ordinary rock-like heft (specific gravity about 2.4), similar to quartz. |
Breccia look-alikes and how to tell them apart
Both sit near Mohs 3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Breccia vs Calcite →
Conglomerate is harder (Mohs 3–7) than Breccia (Mohs 3.5), so Conglomerate will scratch Breccia and not the other way round. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not. Breccia vs Conglomerate →
Both sit near Mohs 3.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Breccia vs Travertine →
Breccia identification FAQ
How can you tell if a rock is Breccia?
Check the color (variable), the varies luster, a Mohs hardness of 3.5 and a variable; test individual minerals streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Breccia?
Breccia has a Mohs hardness of 3.5. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
What is the difference between Breccia and Calcite?
Breccia (Mohs 3.5, varies luster) and Calcite (Mohs 3, vitreous luster) look alike, but hardness, streak and heft usually separate them. See the full Breccia vs Calcite comparison for a side-by-side table.
Is Breccia worth anything?
Entry-level Breccia specimens sell for around $1, typical collector pieces about $10, and premium examples $75 or more depending on size, quality and locality.
What color is Breccia?
Breccia is most often . Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
