Name/Title
RhodochrositeEntry/Object ID
2004.1.1Description
Chemical Composition: (Mn^2+CO3),(SiO2),(ZnFe)^
Crystal System: Triclinic System
Description: Common Name: Rhodochrosite
Chemistry: MnCO3, Manganese Carbonate
Class: Carbonates
Group: Calcite Group
Uses: As a minor ore of manganese, an ornamental and semi-precious gemstone and as mineral specimens.
Location: Found at Sweet Home Mine, Colorado USA
Description: This specimen is as large sits on pyrite, quartz and sphalerite crystals on a matrix
Estimated Value: $250,000
PHYSICAL CHARACTERISTICS:
Color is red to pink, sometimes almost white, yellow and brown.
Luster is vitreous to resinous.
Transparency: Crystals are transparent to translucent.
Crystal System is trigonal; bar 3 2/m.
Crystal Habits include the rhombohedrons and scalahedrons with rounded or curved faces that can obscure the crystal shape. Some crystals can be flattened to a bladed habit and these are sometimes aggregated into rosettes or minute crystals into spherules. Also botryoidal, globular, stalactitic, layered, nodular, vein-filling and granular. Twinning is somewhat common forming penetration twins and contact twins similar to calcite's twins.
Cleavage is perfect in three directions forming rhombohedrons.
Fracture is uneven.
Hardness is 3.5 - 4.
Specific Gravity is approximately 3.5 (above average)
Streak is white.
Other Characteristics: Pink and white banding in massive forms, non-fluorescence and specimens effervesce easily with dilute acids.
Associated Minerals: include calcite, ankerite, alabandite, rhodonite, bementite, spessartine, fluorite, manganite, quartz and many metal sulfides.
Best Field Indicators are color, crystal habit, reaction to acid, non-fluorescence and perfect cleavage.
Fracture: Uneven
Grain Size: Crystalline
Hardness: 4 Flourite
Luster: Vitreous
Occurrence: Occurs in hyrdrothermal veins, in the oxidation zone, as lenticular particles and large deposits in metamorphic rocks.
Colorado officially named rhodochrosite as its state mineral in 2002 based on a proposal by a local high school (Platte Canyon High School in Bailey,Colorado). The reason for this lies in the fact that while the mineral is found worldwide, large red crystals are found only in a few places on earth, and some of the best specimens have been found in the Sweet Home Mine near Alma, Colorado.
Notable Occurrences are numerous and include the famous Sweet Home Mine, Alma, Park County and American Tunnel, Silverton, Colorado; Butte, Montana; the mines of Franklin, New Jersey; Humboldt Mine, Cochise County, Arizona and many sites in California, USA. Also found in Catamarca, Argentine; Huaron Mine and several mines in Ancash Department, Peru; Kara oba, Kazakhatan; Sacrimb, Transylvania, Romania; Cornwall, England; Harz Mountains, Germany; Tsumeb, Otavi, Namibia; Santa Eulalia and Magdalena, Mexico; N'Chwanging Mine, Hotazel, South Africa; Mont Saint-Hilaire, Quebec, Canada and many other localities from around the world.
Rock Color: Light
Rock Type: Sedimentary
Specific Gravity: 3.5
Streak: White
Texture: crystalline
Variety: Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its (rare) 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 crystallizes in the trigonal system. The cleavage is typical rhombohedral carbonate cleavage in three directions. Crystal twinning often is present. It is transparent to translucent with refractive indices of n?=1.814 to 1.816, ne=1.596 to 1.598. It is often confused with the manganese silicate, rhodonite, but is distinctly softer.Collection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
6-3/4 inDepth
5-1/2 inLength
9 inWeight
6.61 ozDimension Notes
Dimension taken at widest pointsLocation
Category
PermanentMoved By
Curtis GardnerDate
May 25, 2023Notes
Added current location