Name/Title
ManganiteEntry/Object ID
2014.1.38Description
Chemical Composition: Al(OH)3
Crystal System: Hexagonal System
Description: Common Name: Manganite
Chemistry: MnO(OH)
Group: Oxides and Hydroxides
Location: Ontario, Canada
Description: Small specimen with a reddish-brown matrix and metallic radial crystalline formations throughout.
Physical Charateristics:
•Color is black to steel gray.
•Luster is metallic to dull in weather specimens.
•Transparency: Crystals are opaque, translucent in only thin splinters.
•Crystal System is monoclinic; 2/m
•Crystal Habit is typically short prismatic crystals that have a psuedo-orthorhombic shape. The terminations are generally blunted with domes and minor pyramid faces. The crystals are striated lengthwise. Crystals are usually grouped into tight bundles and columnar, massive and fiberous forms are also known. Penetration and contact twinning does occassionally occur.
•Cleavage is perfect in one direction lengthwise and good to fair in two other directions, one lengthwise at near right angles to the first one and one basal.
•Fracture is uneven.
•Hardness is 4
•Specific Gravity is 4.3 (average for metallic minerals)
•Streak is reddish to brownish black.
•Associated Minerals are calcite, barite, garnets, limonite, siderite, pyrolusite and other manganese minerals.
•Other Characteristics: Alters to pyrolusite which can coat the crystals, dulling the luster and can affect a streak test.
•Notable Occurrences include Cornwall, England; Harz Mts., Germany; China; Sterling Hill, New Jersey and Negaunee, Michigan, USA and Ukraine.
•Best Field Indicators are crystal habit, luster, striations, color and streak.
Hardness: 7 Quartz
Rock Type: SedimentaryCollection
RAGM Mineral CollectionDimensions
Height
3 inWidth
1-1/2 inLength
1-3/4 inLocation
Location
Display Case
FS-11Room
Frieda Smith HallBuilding
Crater Rock MuseumCategory
PermanentMoved By
Curtis GardnerDate
December 27, 2023Location
Shelf
Bottom RowCabinet
Case# 20Wall
WestBuilding
Freida Smith HallCategory
Permanent
