About Rhodochrosite – History and Introduction
Rhodochrosite is a manganese mineral that makes an interesting gemstone due to its distinctive raspberry red and pink stripes. Due to its composition, rhodochrosite is also referred to as manganesespar or as raspberryspar with reference to its color. The name rhodochrosite comes from the Greek word, “rhodokhros”, meaning “rose colored”. In Argentina, rhodochrosite stalagmites formed in Inca silver mines that were abandoned centuries ago. Sometimes it is also called “Rosa del Inca” or “Inca rose stone” and it is said that the Incas believed that rhodochrosite was the blood of their former rulers that had turned to stone.
Rhodochrosite occurs in both aggregate and crystal form. The transparent raspberrycolored crystal form is rare and is bought at high prices by collectors. Rhodochrosite is the national gemstone of Argentina and the state mineral of Colorado, due to significant deposits being discovered in both places.
Rhodochrosite can be identified by its raspberry red and pink stripes with zig zag bands. In aggregate form it exhibits these unique markings. It can also be distinguished from other material by its Mohs scale hardness of 4.
Rhodochrosite; Origin and Gemstone Sources
The main rhodochrosite deposits are in Argentina. Other sources include Chile, Mexico, Peru, South Africa and the USA. Rhodochrosite crystals are also found in Romania and Hungary.
Buying Rhodochrosite and Determining Rhodochrosite Gemstone Value
Rhodochrosite is raspberry red and pink. In aggregate form it is striped, often with zig zag patterns. Crystals are deep raspberry red, but rare. Rhodochrosite gets its color from the presence of manganese.
Rhodochrosite Clarity and Luster
Rhodochrosite is generally opaque, though transparent crystals are seen. Transparent crystals are usually heavily included. When polished, rhodochrosite has a vitreous, resinous or pearly luster.
Rhodochrosite Cut and Shape
Rhodochrosite is mostly cut en cabochon or carved. It can also be tumbled or drilled.
Crystals can be faceted, but they are rare and usually heavily included.
Rhodochrosite is not known to be treated or enhanced in any way.
Rhodochrosite Gemological Properties
Chemical Formula: MnCO3 Manganese carbonate
Crystal Structure: Trigonal, rhombohedra
Color: Rose-red to yellowish, striped
Hardness: 4 on the Mohs scale
Refractive Index: 1.600 – 1.820
Density: 3.45 – 3.70
Transparency: Transparent to opaque
Double Refraction or Birefringence: -0.208 to -0.220
Luster: Vitreous, pearly, resinous
Fluorescence: Weak; red