Comparison · Igneous Rocks
Granodiorite vs Monzonite
Granodiorite and Monzonite are easy to confuse because both are igneous rocks. Both sit near Mohs 6–7, 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 Granodiorite and Monzonite
- Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Luster is different: Granodiorite is vitreous to dull (mixed mineral grains) while Monzonite is dull.
- Hold a thin edge to the light: Granodiorite is Opaque, Monzonite is opaque.
- They overlap in gray, pink, and white, but Monzonite also comes in black and green.
Granodiorite vs Monzonite properties
| Property | Granodiorite | Monzonite |
|---|---|---|
| Type | Igneous Rocks | Igneous Rocks |
| Mohs hardness | 6–7 | 6 |
| Luster | Vitreous to dull (mixed mineral grains) | dull |
| Streak | — | Variable; usually light gray |
| Transparency | Opaque | opaque |
| Specific gravity | 2.65–2.73 | 2.75 |
| Crystal system | — | varies |
| Common colors | Light gray, Gray, Pinkish gray, White with dark specks | Gray, Pink, White, Black, Greenish gray |
| Rarity | common | common |
| Typical specimen value | $1–$75+ | $1–$75+ |
Which is more valuable?
Typical specimens of Granodiorite and Monzonite trade in a similar range, around $10.
About Granodiorite
Granodiorite is a coarse-grained intrusive igneous rock compositionally between granite and diorite, containing more plagioclase feldspar than orthoclase feldspar along with quartz, biotite, and hornblende. It crystallizes slowly deep underground, allowing individual mineral grains to grow large enough to see without magnification. Granodiorite makes up a substantial portion of the continental crust and forms the core of many mountain ranges worldwide, including much of the Sierra Nevada batholith.
About Monzonite
Monzonite is a coarse-grained intrusive igneous rock with roughly balanced alkali feldspar and plagioclase and little quartz. It can resemble granite or diorite in hand sample.
Granodiorite vs Monzonite FAQ
Is Granodiorite the same as Monzonite?
No. Both are igneous rocks, but they are distinct rock types with different hardness, streak or luster. Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Granodiorite from Monzonite?
Both sit near Mohs 6–7, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Luster is different: Granodiorite is vitreous to dull (mixed mineral grains) while Monzonite is dull. Hold a thin edge to the light: Granodiorite is Opaque, Monzonite is opaque.
Which is harder, Granodiorite or Monzonite?
Granodiorite is harder: Mohs 6–7 against Mohs 6 for Monzonite.
Which is more valuable, Granodiorite or Monzonite?
Typical specimens of Granodiorite and Monzonite trade in a similar range, around $10.
