Cap Andrahomana, near Fort Dauphin, southeastern Madagascar (type locality of grandidierite), and at Almgjotheii, in the aureole of the Rogaland anorthosite complex, southwestern Norwa
Link to MinDat.org Location Data.
Name Origin:
Named for Gunter Werding, of the Mineralogical Institute, Ruhr University, Bochum, Germany.
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Niven M L , Waters D J , Moore J M , American Mineralogist , 76 (1991) p.246-256, The crystal structure of werdingite, (Mg,Fe)2Al12(Al,Fe)2Si4(B,Al)4O37, and, its relationship to sillimanite, mullite and grandidierite
Physical Properties of Werdingite
Cleavage:
{???} Indistinct
Color:
Brownish yellow.
Density:
3.04
Diaphaneity:
Translucent
Habit:
Anhedral Grains - Granular minerals without the expression of crystal shapes
Hardness:
7 - Quartz
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Werdingite
Gladstone-Dale:
CI meas= -0.012 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= 0.004 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2061,KPDmeas= 0.2095,KC= 0.207 Ncalc = 1.63 - 1.64
Optical Data:
Biaxial (-), a=1.614, b=1.646, g=1.651, bire=0.0370, 2V(Calc)=42, 2V(Meas)=33-42. Dispersion r > v moderately strong.
Pleochroism (x):
colorless.
Pleochroism (y):
yellow.
Pleochroism (z):
colorless.
Calculated Properties of Werdingite
Electron Density:
Bulk Density (Electron Density)=3.04 gm/cc note: Specific Gravity of Werdingite =3.09 gm/cc.
Fermion Index:
Fermion Index = 0.01 Boson Index = 0.99
Photoelectric:
PEWerdingite = 2.61 barns/electron U=PEWerdingite x rElectron Density= 7.93 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Werdingite is Not Radioactive
Werdingite Classification
Dana Class:
56.03.02.01(56)Sorosilicate Si2O7 Groups and O, OH, F. and H2O