Comparison · Igneous Rocks
Granite vs Rhyolite
Granite and Rhyolite 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 Rhyolite
- 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, Rhyolite is Opaque.
- They overlap in pink, gray, and white, but Granite also comes in black and Rhyolite also comes in brown, red, and multicolored.
Granite vs Rhyolite properties
| Property | Granite | Rhyolite |
|---|---|---|
| Type | Igneous Rocks | Igneous Rocks |
| Mohs hardness | 6.5 | 5.5–7 |
| Luster | vitreous | Dull to vitreous (glassy groundmass) |
| Streak | Variable; test individual minerals | — |
| Transparency | opaque | Opaque |
| Specific gravity | 2.7 | 2.35–2.7 |
| Crystal system | varies | — |
| Common colors | Pink, Gray, White, Black | Pink, Gray, Tan, Red, White, Banded |
| Rarity | common | common |
| Typical specimen value | $1–$50+ | $1–$75+ |
Which is more valuable?
Typical specimens of Granite and Rhyolite 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 Rhyolite
Rhyolite is a fine-grained volcanic igneous rock chemically equivalent to granite but formed by rapid cooling of silica-rich lava at or near Earth's surface rather than slow crystallization underground. Its high silica content makes rhyolitic magma extremely viscous, often producing explosive eruptions and distinctive flow-banded textures as the sticky lava moves sluggishly before solidifying. Rhyolite typically appears pale gray, pink, or tan and frequently contains visible bands or streaks recording its flow history.
Granite vs Rhyolite FAQ
Is Granite the same as Rhyolite?
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 Rhyolite?
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, Rhyolite is Opaque. They overlap in pink, gray, and white, but Granite also comes in black and Rhyolite also comes in brown, red, and multicolored.
Which is harder, Granite or Rhyolite?
They are about equally hard, both near Mohs 6.5.
Which is more valuable, Granite or Rhyolite?
Typical specimens of Granite and Rhyolite trade in a similar range, around $10.
