Comparison · Sedimentary Rocks vs Carbonates
Dolomite vs Magnesite
Dolomite and Magnesite are easy to confuse. Both sit near Mohs 3.5–4, 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 Dolomite and Magnesite
- Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
- Hold a thin edge to the light: Dolomite is Opaque, Magnesite is translucent.
- They overlap in gray, brown, and yellow, but Dolomite also comes in white and pink and Magnesite also comes in clear.
Dolomite vs Magnesite properties
| Property | Dolomite | Magnesite |
|---|---|---|
| Type | Sedimentary Rocks | Carbonates |
| Mohs hardness | 3.5–4 | 4 |
| Luster | Vitreous to dull | vitreous |
| Streak | White | White |
| Transparency | Opaque | translucent |
| Specific gravity | 2.8–2.9 | 3 |
| Crystal system | — | trigonal |
| Common colors | White, Gray, Pink, Brown, Yellow | White, Gray, Yellowish, Brown, Colorless |
| Rarity | common | common |
| Typical specimen value | $1–$75+ | $3–$150+ |
Which is more valuable?
Magnesite is usually the more valuable of the two: a typical collector specimen runs about $25 against $10 for Dolomite, and premium Magnesite can reach $150 or more.
About Dolomite
Dolomite refers both to the mineral calcium magnesium carbonate, CaMg(CO3)2, and to dolostone, the sedimentary rock composed largely of that mineral. Dolostone typically forms when magnesium-rich water alters existing limestone after deposition, replacing some of the original calcium with magnesium in a process still actively studied by geologists. The rock is usually pale gray, tan, or pinkish and weathers into rounded, pitted outcrops distinct from sharper limestone cliffs.
About Magnesite
Magnesite is a magnesium carbonate mineral that forms white to gray crystalline masses and, less commonly, rhombohedral crystals. It is an important source of magnesium and refractory magnesia.
Dolomite vs Magnesite FAQ
Is Dolomite the same as Magnesite?
No. Dolomite is a sedimentary rock while Magnesite is a carbonate. Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead.
How can you tell Dolomite from Magnesite?
Both sit near Mohs 3.5–4, so a scratch test alone will not separate them. Lean on luster, streak and heft instead. Hold a thin edge to the light: Dolomite is Opaque, Magnesite is translucent. They overlap in gray, brown, and yellow, but Dolomite also comes in white and pink and Magnesite also comes in clear.
Which is harder, Dolomite or Magnesite?
They are about equally hard, both near Mohs 3.5–4.
Which is more valuable, Dolomite or Magnesite?
Magnesite is usually the more valuable of the two: a typical collector specimen runs about $25 against $10 for Dolomite, and premium Magnesite can reach $150 or more.
