Dolomite

Crystal system · Trigonal

Dolomite is a carbonate mineral prized by collectors for its exceptional color range, with several world-class Chinese localities.

Calcium magnesium carbonate (CaMg(CO3)2); trigonal/hexagonal. Forms rhombohedral crystals, often pearly white.

About Dolomite

Dolomite is a carbonate mineral in the dolomite group and has the chemical formula CaMg(CO3)2. It crystallizes in the trigonal system and is one of the most visually varied minerals in the collector market. Its combination of structural character and global distribution make it a recognized species in both systematic and aesthetic collections.

Identification & care

Specimens usually show rhombohedral crystals with characteristic curved 'saddle' faces (baroque dolomite); also massive, granular, columnar. Its color range is broad, including white, colorless, gray, pinkish, yellowish, and brownish. The luster is vitreous, pearly, the streak is white, and specimens range from transparent to translucent. The cleavage is perfect on {10-14} — three directions forming rhombohedra. The fracture is subconchoidal to uneven, which aids identification.

Collector context

How it forms

In terms of geology, Dolomite forms in sedimentary — diagenesis of limestone; hydrothermal veins; metamorphic (dolomite marble); diagenetic replacement of calcite. It is commonly found in association with calcite, quartz, siderite, magnesite, sulfides, fluorite.

Classic Chinese localities

Documented Chinese occurrences are recorded at Shangbao Mine, Jiama Cu-polymetallic deposit and Xianghualing Sn-polymetallic ore field, among others.

Why collectors care

Dolomite is a frequently-sought species in serious collections because its habit is recognizable, its color often strong, and its best examples unmistakable even at a distance. Chinese material has driven much of the recent visual shift in the species — sharper crystals, deeper colors, cleaner matrix.

What affects value

Value in Dolomite is assessed, in typical order of weight, against: (1) locality provenance; (2) size relative to the species norm; (3) crystal form and termination sharpness; (4) color saturation and zoning; (5) transparency and internal clarity; (6) matrix quality and aesthetic balance; (7) condition (absence of damage, chips, or repair). Cleaning quality and verified locality documentation act as multipliers across the above.

Naming history

The name Dolomite has a specific etymological and historical context — see Mindat's reference entry for provenance details. We have retained naming data at the record level; published prose is paraphrased from factual fields rather than copied from source.

Available Dolomite specimens

3 specimens