Comparison · Igneous Rocks
Granite vs Pegmatite
Granite and Pegmatite are easy to confuse because both are igneous rocks. Both sit near Mohs 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 Granite and Pegmatite
- Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Granite is opaque, Pegmatite is Opaque (individual crystals may be transparent).
- They overlap in pink, gray, and white, but Granite also comes in black and Pegmatite also comes in multicolored.
Granite vs Pegmatite properties
| Property | Granite | Pegmatite |
|---|---|---|
| Type | Igneous Rocks | Igneous Rocks |
| Mohs hardness | 6.5 | 6–7 |
| Luster | vitreous | Vitreous (large crystal faces) |
| Streak | Variable; test individual minerals | — |
| Transparency | opaque | Opaque (individual crystals may be transparent) |
| Specific gravity | 2.7 | 2.6–2.8 |
| Crystal system | varies | — |
| Common colors | Pink, Gray, White, Black | Pink, White, Gray, Multicolored (with tourmaline, etc.) |
| Rarity | common | common |
| Typical specimen value | $1–$50+ | $1–$75+ |
Which is more valuable?
Typical specimens of Granite and Pegmatite trade in a similar range, around $10.
About Granite
Granite is a coarse-grained igneous rock composed mainly of quartz, feldspar, and mica. It's one of the most common rocks in Earth's continental crust.
About Pegmatite
Pegmatite is an exceptionally coarse-grained igneous rock, typically granitic in composition, distinguished by crystals often several centimeters to meters in size, far larger than in ordinary granite. Its unusually large crystals result from crystallizing out of a water- and rare-element-enriched residual melt left over after most of a magma body has already solidified. Pegmatites serve as the primary source of many rare minerals and gemstones, including tourmaline, beryl, spodumene, and topaz.
Granite vs Pegmatite FAQ
Is Granite the same as Pegmatite?
No. Both are igneous rocks, but they are distinct rock types with different hardness, streak or luster. Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Granite from Pegmatite?
Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Granite is opaque, Pegmatite is Opaque (individual crystals may be transparent). They overlap in pink, gray, and white, but Granite also comes in black and Pegmatite also comes in multicolored.
Which is harder, Granite or Pegmatite?
They are about equally hard, both near Mohs 6.5.
Which is more valuable, Granite or Pegmatite?
Typical specimens of Granite and Pegmatite trade in a similar range, around $10.
