2.9" Roselite Crystal Clusters and Calcite on Dolomite - Morocco

 
This is a beautiful association of very richly colored roselite crystal clusters and elongated calcite that formed from a dolomite matrix, collected from the Bou Azer District of Morocco.

Roselite is a monoclinic mineral of the hydrated phosphates group, and has a chemical formula of Ca2Co(AsO4)2 · 2H2O. It gained its name not from the rose color that is generally exhibited by the mineral, but was in fact named in honor of a German mineralogist by the name of Gustav Rose. However, the name is quite fitting, for roselite typically displays a vitreous rose-red to pink color. Darker colored crystals have been known to frequently display marked color zoning due to variations in molecular composition.

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
Roselite, Dolomite & Calcite
LOCATION
Bou Azer District, Morocco
SIZE
2.9 x 2"
SUB CATEGORY
ITEM
#141661