RocksdayGranite vs Tonalite
To tell Granite from Tonalite: Granite has abundant potassium feldspar, often pink.
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 intrusive rock of quartz and plagioclase with almost no potassium feldspar. It looks like a gray granite.
Photo: Ingwik, Public domain
Key differences
- Granite has abundant potassium feldspar, often pink.
Side by side
| Property | Granite | Tonalite |
|---|---|---|
| Type | Igneous rock | Igneous rock |
| Mohs hardness | 6–7 | 6–7 |
| Luster | Granular, sparkly | Granular |
| Colors | Pink, Gray, White, Black | Gray, White, Black |
| Crystal system / structure | Coarse-grained (phaneritic) | Coarse-grained (phaneritic) |
| Specific gravity | 2.63–2.75 | 2.6–2.8 |
| Found in | Sierra Nevada, California; Stone Mountain, Georgia | Tonale Pass, Italy; Coastal Batholith, Peru |
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 tonalite
- Gray, speckled, with glassy quartz.
- Feldspar is white plagioclase, not pink alkali feldspar.
- Dark grains of hornblende or biotite.
Structure: Coarse-grained (phaneritic)
Full Tonalite guide →More comparisons
Frequently asked questions
What is the difference between granite and tonalite?
Granite is an igneous rock with a Mohs hardness of about 6–7 and a granular, sparkly luster, usually pink, gray, white or black. Tonalite is an igneous rock with a Mohs hardness of about 6–7 and a granular luster, usually gray, white or black.
How can you tell granite from tonalite?
Granite has abundant potassium feldspar, often pink.
Could you tell them apart from a blurry close-up?
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