Why they get mixed up
Dolomite, quartzite and marble can all be white or gray with soft veining, and stone yards do not always name them the same way. The names come from what the stone is made of, and that decides how it behaves on a counter.
| Compared | Dolomite | Quartzite | Marble |
|---|---|---|---|
| Main mineral | Dolomite (calcium magnesium carbonate) | Quartz | Calcite (calcium carbonate) |
| Hardness (Mohs) | About 3.5 to 4 | About 7 | About 3 |
| Etches from acids | Slowly | No | Yes, quickly |
| Scratches from a knife | Can | No | Yes |
| Needs sealing | Yes | Usually | Yes |
| Heat | Tolerates heat | Tolerates heat | Tolerates heat |
Dolomite
Dolomite forms when magnesium-rich water alters limestone. Polished, it looks much like marble, often with a slightly softer, more even background. Because the mineral dolomite is a little harder and less reactive than calcite, a spill of lemon juice or vinegar takes longer to leave a mark. It will still etch if acid sits on it, so wipe spills promptly and use coasters under citrus drinks and wine.
See our dolomite countertops for the colors we stock and their prices.
Quartzite
Quartzite began as quartz sandstone and was fused by heat and pressure into a dense, glassy stone. It is as hard as engineered quartz and does not etch, which makes it the toughest of the three. It is also the hardest to cut and polish, which shows up in fabrication prices. Do not confuse it with engineered quartz, which is a factory product with resin in it.
Marble
Marble is recrystallized limestone. It is soft and reacts quickly with acids. On a polished marble counter, a ring from a lemonade glass can appear in minutes. A honed (matte) finish hides etches better than a polished one. People who choose marble usually accept that it will wear and gain character over time.
How to tell them apart
- Ask for a sample or an offcut you can test, and ask the seller what the stone is.
- Glass test: drag a sharp corner of the sample across a piece of glass. Quartzite will scratch glass, because quartz is harder than glass. Marble and dolomite will not.
- Acid test: put a drop of lemon juice or vinegar on the sample for about 15 minutes, then wipe it off. Marble will show a dull spot quickly. Dolomite will be slower and fainter. Quartzite will show nothing.
- Do these tests on a sample, never on a counter you own.
Caring for them
All three are natural stone: clean with a pH-neutral cleaner made for stone, never vinegar, lemon or other acidic or abrasive cleaners. Reseal when water stops beading. See cleaning stone countertops and sealing stone countertops.
Common questions
Is dolomite good for kitchen countertops?
Yes, if you want a marble look and will wipe up acidic spills. It is harder and slower to etch than marble, and it handles heat well.
Is dolomite harder than marble?
A little. The mineral dolomite is about 3.5 to 4 on the Mohs scale, marble’s calcite about 3.
Does quartzite etch?
True quartzite does not. If a stone sold as quartzite etches from lemon or vinegar, it is probably marble or dolomite.