Rhodochrosite is a Manganese Carbonate which are largely pink or red. They can commonly form Rhombohedral or Schalenohedral crystals, also at times botryoidal and "wheat sheaf" and is in the Trigonal crystal system. It is considered part of the Calcite group.
Rhodochrosite can come from many areas in the world, some of the most well known and sought after locales include: Sweet Home Mine in Colorado (USA), The Uchucchacua Mine in Peru, and, The N'Chwaning Mines in South Africa.
What to look for: Color, Luster, Distinctive or Isolated Crystals, Obscure Formations (Example: Wheat Sheaf), Specimens on Matrix, Associations, and, Rare Localities.