Comparison · Igneous Rocks
Aplite vs Tonalite
Aplite and Tonalite are easy to confuse because both are igneous rocks. Both sit near Mohs 6, 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 Aplite and Tonalite
- Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Streak color differs: Aplite leaves a white to pale pink streak on unglazed porcelain, Tonalite leaves white to light gray.
- They overlap in white and gray, but Aplite also comes in pink and brown and Tonalite also comes in black and green.
Aplite vs Tonalite properties
| Property | Aplite | Tonalite |
|---|---|---|
| Type | Igneous Rocks | Igneous Rocks |
| Mohs hardness | 6 | 6 |
| Luster | dull | dull |
| Streak | White to pale pink | White to light gray |
| Transparency | opaque | opaque |
| Specific gravity | 2.65 | 2.75 |
| Crystal system | varies | varies |
| Common colors | White, Pink, Cream, Light gray, Tan | White, Gray, Black, Salt and pepper, Greenish gray |
| Rarity | common | common |
| Typical specimen value | $1–$75+ | $1–$75+ |
Which is more valuable?
Typical specimens of Aplite and Tonalite trade in a similar range, around $10.
About Aplite
Aplite is a light-colored, fine-grained granitic igneous rock. It often appears white, pink, cream, or light gray and may occur as narrow dikes or veins.
About Tonalite
Tonalite is a coarse-grained intrusive igneous rock rich in plagioclase and quartz, with less alkali feldspar than granite. It often looks gray, white, and black speckled.
Aplite vs Tonalite FAQ
Is Aplite the same as Tonalite?
No. Both are igneous rocks, but they are distinct rock types with different hardness, streak or luster. Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Aplite from Tonalite?
Both sit near Mohs 6, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Streak color differs: Aplite leaves a white to pale pink streak on unglazed porcelain, Tonalite leaves white to light gray. They overlap in white and gray, but Aplite also comes in pink and brown and Tonalite also comes in black and green.
Which is harder, Aplite or Tonalite?
They are about equally hard, both near Mohs 6.
Which is more valuable, Aplite or Tonalite?
Typical specimens of Aplite and Tonalite trade in a similar range, around $10.
