The Mineral sphaerocobaltite
Sphaerocobaltite describes a pure cobalt
carbonate, without calcium. Pure Sphaerocobaltite is quite uncommon, as the cobalt is usually mixed with calcium. This leads to confusion with the term
Cobaltocalcite. Cobaltocalcite refers to an
intermediary mineral between
Calcite and Sphaerocobaltite in a
solid solution series. It may be described as either a cobalt rich variety of
Calcite, or a calcium rich variety of Sphaerocobaltite.
Sphaerocobaltite belongs to the
calcite group of minerals, a group of
related
carbonates that are
isomorphous with one another. They
are similar in many physical properties, and may partially or fully
replace one another, forming a
solid solution series. All
members of the calcite group
crystallize in the
trigonal
system, and have perfect
rhombohedral cleavage.
Color
Intense pink to reddish-white. Oxidizes brown, dark red, dark maroon, or black.
Properties
Streak
Reddish-white |
Hardness
3.5 - 4 |
Transparency
Transparent to Translucent |
Specific Gravity
4.13 |
Luster
Vitreous |
Cleavage
1,3 - rhombohedral |
Fracture
Conchoidal |
Tenacity
Brittle |
Varieties
-
Cobaltocalcite refers to an intermediary mineral between Calcite and Sphaerocobaltite in a solid solution series. It is most often perceived as a cobalt-rich variety of Calcite with a rich pink color. (Cobaltocalcite may also be mistakenly used as a synonym for Sphaerocobaltite).
Noteworthy Localities
Sphaerocobaltite is a rare mineral. The original type locality is the Daniel mine in Schneedberg, Saxony, Germany. The Kolwezi Mines in Shaba (Katanga), Congo (Zaire) are the most abundant and outstanding source for this mineral. Other occurrences are Bou Azzer, Morocco; Santa Rosalia, Boleo, Baja California, Mexico; and the Cobre Mine, Conception del Oro, Zacatecas, Mexico.
Common Mineral Associations
Calcite, Dolomite, Malachite