Comparison · Igneous Rocks
Gabbro vs Norite
Gabbro and Norite are easy to confuse because both are igneous rocks. Both sit near Mohs 5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Below is a side-by-side comparison of their properties and the quick tests that separate them.
Key differences between Gabbro and Norite
- Both sit near Mohs 5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Luster is different: Gabbro is dull to vitreous (in crystals) while Norite is dull.
- Hold a thin edge to the light: Gabbro is Opaque, Norite is opaque.
- They overlap in gray, black, green, and white, but Gabbro also comes in multicolored and Norite also comes in brown.
Gabbro vs Norite properties
| Property | Gabbro | Norite |
|---|---|---|
| Type | Igneous Rocks | Igneous Rocks |
| Mohs hardness | 5–6.5 | 6 |
| Luster | Dull to vitreous (in crystals) | dull |
| Streak | — | Gray to white |
| Transparency | Opaque | opaque |
| Specific gravity | 2.9–3.1 | 3 |
| Crystal system | — | varies |
| Common colors | Dark gray, Black, Greenish black, Speckled black and white | Black, Dark gray, White, Greenish black, Brown |
| Rarity | common | common |
| Typical specimen value | $1–$75+ | $1–$75+ |
Which is more valuable?
Typical specimens of Gabbro and Norite trade in a similar range, around $10.
About Gabbro
Gabbro is a coarse-grained, dark-colored intrusive igneous rock composed mainly of calcium-rich plagioclase feldspar and pyroxene, with the plutonic equivalent of basalt. It forms deep underground where mafic magma cools slowly enough for its mineral grains to grow large and interlock visibly. Its dense, speckled black-and-white texture makes it a popular dimension stone sold commercially as black granite.
About Norite
Norite is a coarse-grained mafic intrusive igneous rock similar to gabbro but richer in orthopyroxene. It often looks dark, speckled, and dense.
Gabbro vs Norite FAQ
Is Gabbro the same as Norite?
No. Both are igneous rocks, but they are distinct rock types with different hardness, streak or luster. Both sit near Mohs 5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Gabbro from Norite?
Both sit near Mohs 5–6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Luster is different: Gabbro is dull to vitreous (in crystals) while Norite is dull. Hold a thin edge to the light: Gabbro is Opaque, Norite is opaque.
Which is harder, Gabbro or Norite?
They are about equally hard, both near Mohs 5–6.5.
Which is more valuable, Gabbro or Norite?
Typical specimens of Gabbro and Norite trade in a similar range, around $10.
