4.9" Calcite and Dolomite Crystal Association - China

 
 
 
This is a unique mineral association that contains primarily pristine calcite crystals that formed in association with dolomite. It was collected from Manoshan in the Hunan Province of China. The dolomite is tan/yellow in color and has a bladed appearance. The calcite is relatively clear to grey in color, and under UV light, fluoresces a faint orange color. Both sides of this specimen contain calcite crystals with only a small portion of rock that contains no crystals, hence the inclusion of an acrylic display stand to assist with preferred presentation.

Calcite, CaCO3, is a carbonate mineral and the most stable polymorph of calcium carbonate. The other polymorphs are the minerals aragonite and vaterite. Calcite crystals are trigonal-rhombohedral, though actual calcite rhombohedra are rare as natural crystals. However, they show a remarkable variety of habits including acute to obtuse rhombohedra, tabular forms, and prisms. Calcite exhibits several twinning types adding to the variety of observed forms. It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form.

Dolomite is an anhydrous carbonate mineral composed of calcium magnesium carbonate—CaMg(CO3)2.

The mineral dolomite crystallizes in the trigonal-rhombohedral system. It forms white, tan, gray, or pink crystals. Dolomite is a double carbonate, having an alternating structural arrangement of calcium and magnesium ions. It does not rapidly dissolve in dilute hydrochloric acid as calcite does. Crystal twinning is common.

The mineral dolomite was first described by Carl Linnaeus in 1768 and In 1791, it was described as a rock by the French naturalist and geologist Déodat Gratet de Dolomieu who first recognized the material in buildings of the old city of Rome, and later as samples collected in the mountains known as the Dolomite Alps of northern Italy.
DETAILS
SPECIES
Calcite & Dolomite
LOCATION
Manoshan, Hunan Province, China
SIZE
4.9" long, 4.5" tall
CATEGORY
ITEM
#91075