In lenses and bands of barium silicate metasediments developed under hornblende-pyroxene hornfels facies near the contact with granite or granodiorite.
IMA Status:
Approved IMA 1981
Locality:
From Big Creek and Rush Creek, Fresno Co., and on Trumbull Peak, near Incline, Marisopa Co., California, USA. Link to MinDat.org Location Data.
Name Origin:
To honor Dr. John T. Alfors (1930- ), geologist, California Division of Mines, for his work on the type locality.
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Hata M , Marumo F , Iwai S , Aoki H , Acta Crystallographica, Section B , 35 (1979) p.2382-2384, Structure of barium chlorapatite
Physical Properties of Alforsite
Color:
Colorless.
Density:
4.73
Diaphaneity:
Transparent
Hardness:
5 - Apatite
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Alforsite
Gladstone-Dale:
CI meas= -0.005 (Superior) - where the CI = (1-KPDmeas/KC) CI calc= 0.012 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1455,KPDmeas= 0.148,KC= 0.1473 Ncalc = 1.7 - 1.71
Optical Data:
Uniaxial (-), e=1.7, w=1.7, bire=0.0000.
Calculated Properties of Alforsite
Electron Density:
Bulk Density (Electron Density)=4.11 gm/cc note: Specific Gravity of Alforsite =4.73 gm/cc.
Fermion Index:
Fermion Index = 0.12 Boson Index = 0.88
Photoelectric:
PEAlforsite = 314.92 barns/electron U=PEAlforsite x rElectron Density=1,295.80 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Alforsite is Not Radioactive
Alforsite Classification
Dana Class:
41.08.05.02(41)Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen