Sedimentary Rocks · common
Dolostone
Dolostone is a carbonate sedimentary rock composed mostly of the mineral dolomite. It often resembles limestone but may react more weakly with dilute acid.
Also known as: Dolomite rock, Dolomitic limestone.
Dolostone properties at a glance
| Type | Sedimentary Rocks |
|---|---|
| Chemical formula | CaMg(CO3)2 dominant rock |
| Mohs hardness | 3.5 |
| Luster | dull |
| Streak | White |
| Cleavage | Variable by mineral grains |
| Fracture | Uneven to granular |
| Specific gravity | 2.85 |
| Transparency | opaque |
| Common colors | Tan, Gray, White, Cream, Brown |
| Rarity | common |
Geology & background
Forms when limestone or carbonate sediment is altered by magnesium-rich fluids, replacing some calcite with dolomite.
Dolostone is an important reservoir and building stone in many sedimentary basins.
How to identify Dolostone
- Compare with limestone: dolostone often reacts more weakly with dilute acid.
- Look for tan, gray, cream, or buff carbonate rock with granular texture.
- Powdered dolostone may fizz more noticeably than a fresh flat surface.
- Do not confuse the rock dolostone with individual dolomite crystals.
Full Dolostone identification guide: checklist, home tests and look-alikes →
Dolostone vs similar stones
Not sure it isn't something else? Side-by-side comparisons with the stones most often confused with Dolostone.
Where Dolostone is found
Dolostone occurs in many sedimentary settings worldwide; exact locality should be verified from field notes, maps, or specimen provenance.
How much is Dolostone worth?
| Entry-level specimen | $1 |
|---|---|
| Typical collector specimen | $10 |
| Premium specimen | $75+ |
Dolostone is usually valued for teaching, field context, locality, texture, fossils, color, or unusual structures rather than high gem value.
Common uses
- Field identification
- Building stone
- Aggregate
- Cement and lime products
- Education
Interesting facts
- Dolostone is the rock name; dolomite is the mineral name.
- It commonly forms by alteration of limestone after deposition.
- Fresh dolostone often reacts weakly with acid unless powdered.
Care & safety
Dolostone can be soft, porous, crumbly, or weakly cemented depending on grain size, cement, and weathering.
Avoid inhaling dust. Do not cut, grind, or polish unknown sedimentary rocks without eye protection and a properly rated respirator.
Dolostone FAQ
What is Dolostone?
Dolostone is a carbonate sedimentary rock composed mostly of the mineral dolomite. It often resembles limestone but may react more weakly with dilute acid.
How much is Dolostone worth?
Entry-level Dolostone specimens sell for around $1, a typical collector specimen for about $10, and premium pieces for $75 or more. Dolostone is usually valued for teaching, field context, locality, texture, fossils, color, or unusual structures rather than high gem value.
How hard is Dolostone?
Dolostone has a Mohs hardness of 3.5. A steel knife blade (Mohs 5.5) scratches it; a copper coin does not.
What is Dolostone used for?
Dolostone is used for field identification, building stone, aggregate, cement and lime products, and education.
