RocksdayGranite vs Monzonite
How to tell them apart
A coarse-grained rock that cooled slowly deep underground, made of quartz, feldspar and mica or hornblende.
Photo: The stone gate, CC BY-SA 4.0
A coarse rock with roughly equal pink alkali feldspar and white plagioclase, and little quartz.
Photo: Courtesy NASA/JPL-Caltech, Public domain
Key differences
- Granite has more quartz.
Side by side
| Property | Granite | Monzonite |
|---|---|---|
| Type | Igneous rock | Igneous rock |
| Mohs hardness | 6–7 | 6 |
| Luster | Granular, sparkly | Granular |
| Colors | Pink, Gray, White, Black | Gray, Pink, White |
| Crystal system / structure | Coarse-grained (phaneritic) | Coarse-grained (phaneritic) |
| Specific gravity | 2.63–2.75 | 2.7–2.8 |
| Found in | Sierra Nevada, California; Stone Mountain, Georgia | Monzoni, Italy; Bingham Canyon, Utah |
Properties that are the same for both are grayed out.
How to identify granite
- Speckled with interlocking grains you can see without a lens.
- Glassy gray quartz plus pink or white blocky feldspar.
- Black specks of mica or hornblende.
- Hard, with no layering or banding.
Structure: Coarse-grained (phaneritic)
Full Granite guide →How to identify monzonite
- Mix of pink and white feldspar.
- Some dark minerals, little quartz.
- Coarse, even grains.
Structure: Coarse-grained (phaneritic)
Full Monzonite guide →More comparisons
Could you tell them apart from a blurry close-up?
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