RocksdayMarble vs Quartzite
How to tell them apart
Limestone recrystallized by heat and pressure into a mosaic of interlocking calcite grains.
Photo: Zyance, CC BY-SA 2.5
Sandstone fused by metamorphism into an extremely hard rock of interlocked quartz grains.
Photo: Gabriel Haute Maurienne, CC BY-SA 4.0
Quick tests
- Scratch glass: Quartzite scratches glass (Mohs 7); Marble can't (Mohs 3–4).
- Acid (vinegar or dilute HCl): Marble fizzes; Quartzite doesn't.
Key differences
- Quartzite is far harder and doesn't fizz.
- Marble is soft and fizzes in acid.
Side by side
| Property | Marble | Quartzite |
|---|---|---|
| Type | Metamorphic rock | Metamorphic rock |
| Mohs hardness | 3–4 | 7 |
| Luster | Sugary sparkle | Sugary to glassy |
| Colors | White, Gray, Pink, Green | White, Pink, Gray |
| Crystal system / structure | Interlocking crystals (non-foliated) | Interlocking quartz grains (non-foliated) |
| Specific gravity | 2.6–2.9 | 2.6–2.7 |
| Found in | Carrara, Italy; Yule, Colorado | Baraboo, Wisconsin; Sioux Falls, South Dakota |
Properties that are the same for both are grayed out.
How to identify marble
- Sparkly, sugary crystals on broken surfaces.
- Fizzes in acid.
- A knife scratches it.
- Often swirled or veined.
Structure: Interlocking crystals (non-foliated)
Full Marble guide →How to identify quartzite
- Breaks through the grains, not around them.
- Scratches glass.
- Smooth, sugary surface — not gritty.
- Doesn't fizz in acid.
Structure: Interlocking quartz grains (non-foliated)
Full Quartzite guide →More comparisons
Could you tell them apart from a blurry close-up?
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