RocksdayGranite vs Rapakivi
To tell Granite from Rapakivi: Ordinary granite feldspars are blocky, not rimmed ovoids.
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
Granite with egg-shaped alkali feldspar crystals, each wrapped in a rim of plagioclase.
Photo: Lysippos, CC BY-SA 3.0
Key differences
- Ordinary granite feldspars are blocky, not rimmed ovoids.
Side by side
| Property | Granite | Rapakivi |
|---|---|---|
| Type | Igneous rock | Igneous rock |
| Mohs hardness | 6–7 | 6–7 |
| Luster | Granular, sparkly | Granular |
| Colors | Pink, Gray, White, Black | Pink, Gray, Brown |
| Crystal system / structure | Coarse-grained (phaneritic) | Ovoid feldspar with plagioclase rims |
| Specific gravity | 2.63–2.75 | 2.6–2.8 |
| Found in | Sierra Nevada, California; Stone Mountain, Georgia | Southern Finland; St. Francois Mountains, Missouri |
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 rapakivi
- Round pink or brown feldspar ovoids.
- A pale rim around many of the ovoids.
- Coarse, with quartz and dark mica or hornblende.
Structure: Ovoid feldspar with plagioclase rims
Full Rapakivi guide →More comparisons
Frequently asked questions
What is the difference between granite and rapakivi?
Granite is an igneous rock with a Mohs hardness of about 6–7 and a granular, sparkly luster, usually pink, gray, white or black. Rapakivi is an igneous rock with a Mohs hardness of about 6–7 and a granular luster, usually pink, gray or brown.
How can you tell granite from rapakivi?
Ordinary granite feldspars are blocky, not rimmed ovoids.
Could you tell them apart from a blurry close-up?
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