The mineral sphaerocobaltite

	Chemical Formula	CoCO₃
	Composition	Cobalt carbonate, usually with some calcium
	Variable Formula	(Co,Ca)CO₃
	Color	Reddish-white on untarnished surfaces. Oxidizes brown, dark red, dark maroon, or black.
	Streak	Reddish-white
	Hardness	3½ - 4
	Crystal Forms and Aggregates	(Hexagonal) Occurs in small rhombohedral crusts and massive.
	Transparency	Transparent to Translucent
	Specific Gravity	4.13
	Luster	Vitreous
	Cleavage	1,3 - rhombohedral
	Fracture	Conchoidal
	Tenacity	Brittle
	Varieties	Cobaltocalcite, Cobalt Calcite, or Cobaltian Calcite - Sphaerocobaltite containing calcium. It is the intermediary form between Sphaerocobaltite and Calcite in a solid solution series. Formula = (Co,Ca)CO₃. (See Cobaltocalcite for more information.)
	In Group	Carbonates ; Calcite group
	All about	Sphaerocobaltite belongs to the calcite group, 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 partial solid solution series. All members of the calcite group crystallize in the trigonal subdivision of the hexagonal system (as rhombohedrons and scalenohedrons), have perfect rhombohedral cleavage, and exhibit a strong double refraction in transparent rhombohedrons. The variety Cobaltocalcite has two connotations. Scientifically, it refers to an intermediary mineral between Calcite and Sphaerocobaltite in a solid solution series. However, it is very often used as a synonym for Sphaerocobaltite by inexperienced dealers.
	Complex Tests	Effervesces in hydrochloric acid
	Popularity (1-4)	3
	Prevalence (1-3)	3
	Demand (1-3)	3
	Commonly Occurs With	Calcite, Dolomite, Malachite
	Noteworthy Localities	Occurs in the Danile mine in Neustadtel, Freiberg, Saxony, Germany; Ruashi, Shaba, Zaire; Boleo, Baja California, Mexico; and Zacatecas, Mexico.
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