Tweddillite
Armbruster T, Gnos E, Dixon R, Gutzmer J, Hejny C, Dobelin N, Medenbach O
Mineralogical Magazine 66 (2002) 137-150
Manganvesuvianite and tweddillite, two new Mn3+-silicate minerals
from the Kalahari manganese fields, South Africa
Locality: Kalahari manganese fields, South Africa
_database_code_amcsd 0014561
8.934 5.718 10.325 90 114.54 90 P2_1/m
atom       x     y      z occ Biso
CaA1   .7646   .75  .1575      .92
SrA2   .5941   .75 .42163     1.03
AlM1       0     0      0 .43  .64
Mn3+M1     0     0      0 .48  .64
Fe3+M1     0     0      0 .09  .64
AlM2       0     0     .5      .66
Mn3+M3 .2954   .25  .2181 5/6  .90
Fe3+M3 .2954   .25  .2181 1/6  .90
Si1    .3417   .75  .0411      .95
Si2    .6877   .25  .2787      .85
Si3    .1803   .75  .3150      .86
O1     .2389 .9915  .0386     1.42
O2     .2984 .9786  .3480     1.14
O3     .7967 .0160  .3433     1.17
O4     .0600   .25  .1312       .9
O5     .0369   .75  .1479      1.0
O6     .0661   .75  .4061      1.0
O7     .5174   .75  .1691      1.4
O8     .5277   .25  .3110      1.0
O9     .6323   .25  .1063      1.8
O10    .0815   .25  .4293       .9
H10      .06   .25   .339     3.95