Formed from acid mine waste waters with mineralogically zoned assemblages in sheltered areas at a relative humidity of 65% and T = 4 °C. Dehydrates to cuprian pentahydrate. Mg-domin ant analog of melanterite.
IMA Status:
Approved IMA 2003 (Dana # Added)
Locality:
Big Mike mine located on the south side of Panther Canyon, on the west flank of the north end of the Tobin Range, Pershing County, Nevada, USA. Link to MinDat.org Location Data.
Name Origin:
Named after Charles N. Alpers, geochemist with the United States Geological Survey, who has made significant contributions to our understanding of the mineralogical controls of mine -water geochemistry.
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Peterson R C , Hammarstrom J M , Seal II R R , American Mineralogist , 91 (2006) p.261-269, Alpersite (Mg,Cu)SO4*7H2O, a new mineral of the melanterite group, and cuprian, pentahydrite: Their occurrence within mine waste, Locality: Big Mike mine, Nevada, USA
View Additional jPOWD Structure files for Alpersite
[1]
Physical Properties of Alpersite
Cleavage:
{001} Good
Color:
Blue.
Diaphaneity:
Transparent
Fracture:
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Habit:
Efflorescences - Crystals covering matrix, generally produced from transpiro-evaporation.
Hardness:
2.5 - Finger Nail
Luster:
Vitreous (Glassy)
Streak:
white
Optical Properties of Alpersite
Gladstone-Dale:
CI calc= -0.002 (Superior) - where the CI = (1-KPDcalc/KC) KPDcalc= 0.2571,KC= 0.2565 Ncalc = 1.46
Optical Data:
Biaxial (+), a=1.462, b=1.465, g=1.469, bire=0.0070, 2V(Calc)=82, 2V(Meas)=79.8. Dispersion r > v weak.
Calculated Properties of Alpersite
Electron Density:
Bulk Density (Electron Density)=1.89 gm/cc note: Specific Gravity of Alpersite =1.81 gm/cc.
Fermion Index:
Fermion Index = 0.0068592789 Boson Index = 0.9931407211
Photoelectric:
PEAlpersite = 5.00 barns/electron U=PEAlpersite x rElectron Density= 9.44 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Alpersite is Not Radioactive