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MINERALS INDEX
Manganbrucite |
| (Mg,Mn,Zn)(OH)2 |
| Hexagonal-rhombohedral |
A single specimen of manganbrucite has been found as a thin veinlet cutting the franklinite-willemite ore at Franklin. The crystals are acicular parallel to the c axis, and the individuals are closely compacted to form subparallel aggregates with curved terminations made up of basal planes not quite parallel to one another. The color ranges from pure white to deep brown, depending presumably on the amount of oxidation the manganese has undergone. The refractive index is not constant but is higher than that of pure brucite. The average values determined were w = 1.59, e =1.60.
The following chemical analysis was made by Bauer on light-colored material and yields a magnesium to manganese ratio of 5 to 1. The material from Jakobsberg has a ratio of 7 to 1.
| H2O | 25.97 |
| MnO | 17.58 |
| ZnO | 3.56 |
| MgO | 49.94 |
| CaO (present as CaCO3) | undetermined |
97.05 |
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Website
© by Herb Yeates 1997-2001.
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This
page created: January 12, 2001 6:32 PM
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