Identification guide · Igneous Rocks
How to Identify Granite
Granite is usually pink, gray, and white with a vitreous luster and is opaque. It has a Mohs hardness of 6.5. It scratches glass and a steel knife and cannot be scratched by a steel file. Its streak is variable; test individual minerals. It is most often confused with Granodiorite, Syenite, and Monzonite; the tests below separate them.
Granite identification checklist
| Color | Pink, Gray, White, Black | Look at a clean, dry surface in daylight. Color zoning, banding or spots are as diagnostic as the hue. |
|---|---|---|
| Luster | Vitreous | Fresh surfaces shine like glass; a dull surface usually means weathering, so chip or wet a corner. |
| Transparency | Opaque | Hold a thin edge up to a bright light and note whether light passes through. |
| Mohs hardness | 6.5 | It scratches glass and a steel knife and cannot be scratched by a steel file. |
| Streak | Variable; test individual minerals | Drag a corner across unglazed porcelain (the back of a bathroom tile) and check the powder color. |
| Cleavage | Variable by mineral grains | |
| Fracture | Uneven | |
| Specific gravity | 2.7 | Ordinary rock-like heft (specific gravity about 2.7), similar to quartz. |
Granite look-alikes and how to tell them apart
Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Granite vs Granodiorite →
Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Granite vs Syenite →
Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Granite vs Monzonite →
Both sit near Mohs 6.5, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Granite vs Tonalite →
Field tips
- Check whether the specimen's color and texture match typical Granite examples.
- Use hardness, streak, luster, grain size, and locality together; no single trait is enough for every specimen.
Granite identification FAQ
How can you tell if a rock is Granite?
Check the color (pink, gray, white, and black), the vitreous luster, a Mohs hardness of 6.5 and a variable; test individual minerals streak. Photographing it with the StoneSnap app gives a match in seconds.
What is the hardness of Granite?
Granite has a Mohs hardness of 6.5. It scratches glass and a steel knife and cannot be scratched by a steel file.
What is the difference between Granite and Granodiorite?
Granite (Mohs 6.5, vitreous luster) and Granodiorite (Mohs 6–7, vitreous to dull (mixed mineral grains) luster) look alike, but hardness, streak and heft usually separate them. See the full Granite vs Granodiorite comparison for a side-by-side table.
Is Granite worth anything?
Entry-level Granite specimens sell for around $1, typical collector pieces about $10, and premium examples $50 or more depending on size, quality and locality.
What color is Granite?
Granite is most often pink, gray, white, and black. Color varies with impurities and locality, so confirm with hardness and luster rather than color alone.
