Manganoan calcite or Manganocalcite is a variety of calcite

Calcite

Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...

 rich in manganese

Manganese

Manganese is a chemical element, designated by the symbol Mn. It has the atomic number 25. It is found as a free element in nature , and in many minerals...

, which gives the mineral a pink color. Its chemical composition is (Ca,Mn)CO₃. It was first reported from the Banská Štiavnica

Banská Štiavnica

Banská Štiavnica is a town in central Slovakia, in the middle of an immense caldera created by the collapse of an ancient volcano. For its size, the caldera is known as Štiavnica Mountains. Banská Štiavnica has a population of more than 10,000. It is a completely preserved medieval town...

 Mining District, Slovak Republic, but is widely distributed around the world, notably at Naica, Chihuahua, Mexico

Mexico

The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

, in the Cave of Swords and Bulgaria.

Manganoan calcite is sometimes confused with rhodochrosite

Rhodochrosite

Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. The streak is white. Its Mohs hardness varies between 3.5 and 4. Its specific gravity is 3.5 to 3.7. It...

. The amount of manganese in manganocalcite varies at different localities, and in fact the mineral forms a solid solution

Solid solution

A solid solution is a solid-state solution of one or more solutes in a solvent. Such a mixture is considered a solution rather than a compound when the crystal structure of the solvent remains unchanged by addition of the solutes, and when the mixture remains in a single homogeneous phase...

 series between calcite and rhodochrosite, with the color becoming redder with a higher proportion of manganese.

External links

• Photo of Manganoan Calcite at the University of Delaware
  University of Delaware
  The university is organized into seven colleges:* College of Agriculture and Natural Resources* College of Arts and Sciences* Alfred Lerner College of Business and Economics* College of Earth, Ocean and Environment* College of Education and Human Development...
  
  
• Manganoan Calcite Gallery