Dolomite

Dolomite is named in honor of the French chemist Deodat de Dolomieu. It is a common sedimentary mineral. Like all carbonates, it commonly forms as rhombehedrons. While dolomite is found in many ancient rocks, it does not form as a sedimentary mineral today. Why? Geologists are still working on that, but believe it may form by alteration of another common carbonate mineral, calcite, exchanging Ca atoms for Mg atoms.

Chemical Formula:

CaMg(CO3)2

Mineral Class:

Carbonate

Crystal System:

Hexagonal

Symmetry:

-3

Hardness:

3.5-4

Specific Gravity:

2.85

Cleavage:

{10-11} perfect

Fracture:

Conchoidal

Color:

Colorless, white, gray, pink, green, brown, black

Streak:

White

Luster:

Vitreous, pearly

Transparency:

Transparent/translucent

Common Habits:

Blocky

Other Properties:

Effervesces in hot HCl

Notable Localities:

Tyrol, Switzerland; Italy; Guanajuato, Mexico; Joplin, Missouri

Uses:

Construction, ornamental stone

Associated Minerals:

Fluorite, calcite, barite, siderite

Specimens:


Dolomite
Hoxie, AR


Dolomite
Tsumeb, Namibia


Dolomite
Minas Gerais, Brazil


Dolomite
Navarre, Spain