Pentahydrite Mineral Data

Pentahydrite Mineral Data +

General Pentahydrite Information

Chemical Formula:

MgSO4·5(H2O)

Composition:

Molecular Weight = 210.45 gm

Magnesium 11.55 % Mg 19.15 % MgO

Hydrogen 4.79 % H 42.80 % H₂O

Sulfur 15.24 % S 38.05 % SO₃

Oxygen 68.42 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg(SO₄)·5(H₂O)

Environment:

Pseudomorphs of dehydration of epsomite.

IMA Status:

Valid Species (Pre-IMA) 1951

Locality:

The Geysers, Sonoma County, California, USA. Link to MinDat.org Location Data.

Name Origin:

Named from the Greek, penta, "five" and hydros "water" in allusion to the 5 water molecules in the formula.

Synonym:

ICSD 2776

PDF 25-532

Pentahydrite Image

Images:

Pentahydrite

Comments: White, powdery pentahydrite.
Location: Shaft 371, Schlema-Hartenstein area, Erzgebirge, Saxony, Germany. Scale: Picture size 4 mm.
© Thomas Witzke / Abraxas-Verlag

Pentahydrite Crystallography

Axial Ratios:

a:b:c =0.6004:1:0.5758

Cell Dimensions:

a = 6.335, b = 10.55, c = 6.075, Z = 2; alpha = 99.17°, beta = 109.88°, gamma = 75° V = 364.10 Den(Calc)= 1.92

Crystal System:

Triclinic - PinacoidalH-M Symbol ( 1) Space Group: P1

Crystal Structure:

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Help on Above

Peterson R C , Hammarstrom J M , Seal 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 Pentahydrite
[1] [2]

Physical Properties of Pentahydrite

Cleavage:

None

Color:

White, Light blue, Light greenish blue.

Density:

1.9

Diaphaniety:

Transparent to Translucent

Habit:

Efflorescences - Crystals covering matrix, generally produced from transpiro-evaporation.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

2.5 - Finger Nail

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Pentahydrite

Gladstone-Dale:

CI meas= -0.025 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.014 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2547,KPDmeas= 0.2574,KC= 0.2512

Optical Data:

Biaxial (-), a=1.482, b=1.492, g=1.493, bire=0.0110, 2V(Calc)=34, 2V(Meas)=45.13.

Calculated Properties of Pentahydrite

Electron Density:

r_electron=2.01 gm/cc
note: r_Pentahydrite=1.92 gm/cc.

Fermion Index

Fermion Index = 0.01302
Boson Index = 0.98698

Photoelectric:

PE_Pentahydrite= 1.29 barns/electron
U=PE_Pentahydrite x r_electron= 2.58 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pentahydrite is Not Radioactive

Pentahydrite Classification

Dana Class:

29.6.7.3 (29)Hydrated Acid and Sulfates

(29.6)where A XO4 · x(H2O)

(29.6.7)Chalchanthite Group (Triclinic: P1¯)

29.6.7.1 Chalcanthite CuSO4·5(H2O) P1 1

29.6.7.2 Siderotil FeSO4·5(H2O) P1 1

29.6.7.3 Pentahydrite MgSO4·5(H2O) P1 1

29.6.7.4 Jokokuite MnSO4·5(H2O) P1 1

Strunz Class:

VI/C.04-10 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/C - Water-bearing sulfates without unfamiliar anions. cations of medium size

VI/C.04 - Chalcanthite group

VI/C.04-10 Pentahydrite MgSO4·5(H2O) P1 1

VI/C.04-20 Siderotil FeSO4·5(H2O) P1 1

VI/C.04-30 Jokokuite MnSO4·5(H2O) P1 1

VI/C.04-40 Chalcanthite CuSO4·5(H2O) P1 1

Other Pentahydrite Information

References:

NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Pentahydrite :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Crocoite.com Mineral Locations 4 - EUROmin Project 5 -Google Images 6 -Google Scholar 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 - WWW-MINCRYST 13 -École des Mines de Paris

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Print or Cut-and-Paste your Pentahydrite Specimen Label here :

Pentahydrite

MgSO4·5(H2O)
Dana No: 29.6.7.3 Strunz No: VI/C.04-10
Locality:

Notes: