Provenite

About Dolomite

CaMg(CO₃)₂

Calcium-magnesium carbonate and one of the major rock-forming minerals; collectors know it best as curved, saddle-shaped or sharp rhombohedral crystals, with pink cobalt-bearing material from Katanga among the most colourful.

Show 24 localities on the map

Photos of Dolomite

Plate of lustrous flesh-pink dolomite rhombs edged with pyrite cubes and a little purple fluorite.
Dolomite · Shangbao Pyrite Mine (Leiyang)
Plate of lustrous flesh-pink dolomite rhombs edged with pyrite cubes and a little purple fluorite.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Bright pink cobaltoan dolomite cast after calcite with a sponge-like appearance.
Dolomite · Tsumeb Mine
Bright pink cobaltoan dolomite cast after calcite with a sponge-like appearance.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Lustrous vivid pink cobaltoan dolomite rhombs lining a vug in matrix.
Dolomite · Mashamba West Mine (Kolwezi)
Lustrous vivid pink cobaltoan dolomite rhombs lining a vug in matrix.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Water-clear, highly lustrous penetration-twinned dolomite crystal.
Dolomite · Azcarate Quarry (Eugui)
Water-clear, highly lustrous penetration-twinned dolomite crystal.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Pocket wall completely lined with lustrous deep pink cobaltoan dolomite crystals (Kolwezi).
Dolomite · Kolwezi area (Musonoi mine)
Pocket wall completely lined with lustrous deep pink cobaltoan dolomite crystals (Kolwezi).
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Twinned dolomite crystal with gemmy, lustrous edges, resembling a sandwich.
Dolomite · Serra das Eguas (Brumado)
Twinned dolomite crystal with gemmy, lustrous edges, resembling a sandwich.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Large plate of shimmering salmon-pink dolomite crystals with small chalcopyrites.
Dolomite · Black Rock (Lawrence County Zinc District)
Large plate of shimmering salmon-pink dolomite crystals with small chalcopyrites.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source
Rosette of glassy, flattened gray dolomite crystals with pyrrhotite on quartz.
Dolomite · Morro Velho Mine (Nova Lima)
Rosette of glassy, flattened gray dolomite crystals with pyrrhotite on quartz.
Photo: Robert M. Lavinsky · CC BY-SA 3.0 · Source

Where Dolomite is found (24)

Brazil

Canada

China

Democratic Republic of the Congo

Mexico

Morocco

Namibia

Portugal

Romania

Slovakia

Spain

Switzerland

United Kingdom

United States

Dolomite on the same specimen with other minerals

Same specimen Dolomite with Chalcopyrite at Cavnic

1 specimen photo(s) from this locality show chalcopyrite with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Galena at Viburnum Trend

1 specimen photo(s) from this locality show galena with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Galena at Tsumeb Mine

1 specimen photo(s) from this locality show galena with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Sphalerite at Joplin Field

2 specimen photo(s) from this locality show sphalerite with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Pyrite at Sweetwater Mine

1 specimen photo(s) from this locality show pyrite with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrite with Dolomite at Shangbao Pyrite Mine (Leiyang)

1 specimen photo(s) from this locality show dolomite with pyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Fluorite with Dolomite at Shangbao Pyrite Mine (Leiyang)

1 specimen photo(s) from this locality show dolomite with fluorite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Quartz with Dolomite at Serra das Eguas (Brumado)

1 specimen photo(s) from this locality show dolomite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Hematite with Dolomite at Serra das Eguas (Brumado)

1 specimen photo(s) from this locality show dolomite with hematite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Pyrrhotite with Dolomite at Morro Velho Mine (Nova Lima)

1 specimen photo(s) from this locality show dolomite with pyrrhotite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Quartz with Dolomite at Morro Velho Mine (Nova Lima)

1 specimen photo(s) from this locality show dolomite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Calcite with Dolomite at Black Rock (Lawrence County Zinc District)

1 specimen photo(s) from this locality show dolomite with calcite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Chalcopyrite with Dolomite at Black Rock (Lawrence County Zinc District)

1 specimen photo(s) from this locality show dolomite with chalcopyrite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Hematite with Dolomite at Beckermet Mine (Egremont)

1 specimen photo(s) from this locality show dolomite with hematite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Quartz with Dolomite at Banska Stiavnica

2 specimen photo(s) from this locality show dolomite with quartz together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Siderite at Morro Velho Mine

1 specimen photo(s) from this locality show siderite with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Same specimen Dolomite with Siderite at Neudorf (Harzgerode)

1 specimen photo(s) from this locality show siderite with dolomite together. The pairing comes from the photographer's file name and label, so the relationship between the two minerals is not specified.

Identity

Group
Dolomite group
Strunz
5 Carbonates and nitrates
Name origin
Named after the French geologist and naturalist Deodat de Dolomieu (1750-1801), who contributed early descriptions of the mineral in dolostone.
Elements
Ca, Mg, C, O

Physical properties

Color
Colorless, white, yellow, brown, pale pink; cobalt-bearing material pink to hot pink, copper-bearing material greenish
Streak
White
Luster
Vitreous luster
Transparency
Variable
Mohs hardness
3.5–4
Density
2.86–2.876 g/cm³
Cleavage / fracture
Perfect rhombohedral cleavage on {10-11}; parting on {02-21}; fracture subconchoidal; brittle
Magnetism / fluorescence
May fluoresce white to pink under UV; triboluminescent

Crystallography

Crystal system
Trigonal
Space group
R-3
Structure
Rhombohedral cell with a = 4.812 A, c = 16.020 A, Z = 3; refined together with calcite, magnesite, siderite and related calcite-type carbonates.
Typical habit
Rhombohedra {10-11} combined with {11-20}, tabular on {0001}, often with curved faces; saddle-shaped aggregates; also columnar, stalactitic, granular and massive; crystals to 20 cm
Twinning
Simple contact twins on {0001}, {10-10} or {11-20}, common; lamellar twinning on {02-21}
Optical data
Uniaxial (-), sometimes anomalously biaxial with small 2V; omega = 1.679, epsilon = 1.500; colorless in transmitted light

Formation and use

Formation
Forms by diagenesis or hydrothermal replacement of limestone, as a primary phase in hypersaline sediments, in marbles and contact-metamorphic rocks, as gangue in hydrothermal veins, and in carbonatites and ultramafic rocks.
Uses
Main constituent of dolostone, a rock with numerous commercial uses; collector specimens.

Related minerals

Related minerals
Ankeritekutnohorite

Sources

  1. SRC-471 · Book
    Handbook of Mineralogy - DolomiteAnthony, J.W.; Bideaux, R.A.; Bladh, K.W.; Nichols, M.C. · 2005 · Mineral Data Publishing / Mineralogical Society of America
  2. SRC-472 · Website
    Dolomite - Gallery (Minerals.net)Minerals.net · Minerals.net

Draft data from the Provenite workbook. Check entries against the cited sources before relying on them. Photos are open-licence images from Wikimedia Commons; the author and licence are given with each photo.