Name/Title
RhodochrositeEntry/Object ID
2004.1.7Description
Assemblage Zone: hydrothermal precipitatio
Chemical Composition: Mn^2+CO3
Crystal System: Triclinic System
Description: Common Name: Rhodochrosite
Chemistry: MnCO3, Manganese Carbonate
Class: Carbonates
Group: Calcite Group
Found at the Hotazel MIne, Hotazel Kalahari Manganese Fields, Northern Cape, South Africa
Description: This specimen has rosy red pointed crystals
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
Hardness: 4 Flourite
Luster: Vitreous
Occurrence: Ore veins and metamorphic manganese deposits. Most localities are the result of metamorphism, late stage igneous intrusion or more commonly hydrothermal precipitation.
Rock Color: Medium
Rock Type: Metamorphic
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 softerCollection
Suomynona Mineral Collection, Suomynona CollectionAcquisition
Accession
2004.1Source or Donor
Suomynona Mineral CollectionAcquisition Method
DonationDimensions
Width
3-3/4 inDepth
1-1/2 inLength
5 inWeight
1.83 ozDimension Notes
Dimension taken at widest pointsLocation
Category
PermanentMoved By
Curtis GardnerDate
May 25, 2023Notes
Added current location
