In vesicles in contact metamorphosed basement gneiss xenoliths in leucite tephrite (Bellerberg volcano, Germany); an accessory mineral in an enstatite chondrite (Indarch meteorite). Forms a series with eifelite.
IMA Status:
Approved IMA 1966
Locality:
In the Indarch, Witchita County, and Canyon Diablo meteorites. Link to MinDat.org Location Data.
Name Origin:
Named for Edwin Woods Roedder (1919- ), mineralogist, U.S. Geological Survey, who noted the synthetic compound.
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Armbruster T , European Journal of Mineralogy , 1 (1989) p.715-718, Crystal chemistry of double-ring silicates:, structure of roedderite at 100 and 300 K, T= 100 K
CI meas= -0.017 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= 0.021 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1998,KPDmeas= 0.2075,KC= 0.204 Ncalc = 1.53 - 1.55
Optical Data:
Uniaxial (+), w=1.537, e=1.542, bire=0.0050.
Calculated Properties of Roedderite
Electron Density:
Bulk Density (Electron Density)=2.58 gm/cc note: Specific Gravity of Roedderite =2.60 gm/cc.
Fermion Index:
Fermion Index = 0.02 Boson Index = 0.98
Photoelectric:
PERoedderite = 3.68 barns/electron U=PERoedderite x relectron= 9.48 barns/cc.
Radioactivity:
GRapi = 27.10 (Gamma Ray American Petroleum Institute Units)
Concentration of Roedderite per GRapi unit = 3.69 (%)
Estimated Radioactivity from Roedderite - barely detectable