Hexahydrite Mineral Data

General Hexahydrite Information

Chemical Formula:

MgSO4•6(H2O)

Composition:

Molecular Weight = 228.46 gm

Magnesium 10.64 % Mg 17.64 % MgO

Hydrogen 5.29 % H 47.31 % H₂O

Sulfur 14.04 % S 35.05 % SO₃

Oxygen 70.03 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg(SO₄)•6(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1911

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named after the number of water molecules hexa, "six" and hydor, "water."

Name Pronunciation:

Hexahydrite + Pronunciation

Synonym:

Bitter Salt

ICSD 16546

Magnesium Sulphate

PDF 24-719

Hexahydrite Image

Images:

Hexahydrite

Comments: White fibrous mats and powdery encrustation of hexahydrite on matrix.
Location: near Basque, Bonaparte River, British Columbia, Canada. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Hexahydrite Crystallography

Axial Ratios:

a:b:c =3.3871:1:1.4023

Cell Dimensions:

a = 24.442, b = 7.216, c = 10.119, Z = 8; beta = 98.28° V = 1,766.12 Den(Calc)= 1.72

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: A2/a

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 4.39(1), 5.45(0.5), 5.1(0.45),

Crystal Structure:

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drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
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S - Stereo Pair on/off
H - Help Screen
I - Data Info
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Zalkin A , Ruben H , Templeton D H , Acta Crystallographica , 17 (1964) p.235-240, The crystal structure and hydrogen bonding of magnesium sulfate hexahydrate, Locality: synthetic

Physical Properties of Hexahydrite

Cleavage:

{010} Perfect, {101} Distinct

Color:

Colorless, White, Greenish white.

Density:

1.76

Diaphaneity:

Opaque

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Acicular - Occurs as needle-like crystals.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Fibrous - Crystals made up of fibers.

Hardness:

2-2.5 - Gypsum-Finger Nail

Luminescence:

Non-fluorescent.

Luster:

Vitreous (Glassy)

Magnetism:

Nonmagnetic

Streak:

white

Optical Properties of Hexahydrite

Gladstone-Dale:

CI meas= 0.021 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.002 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2587,KPDmeas= 0.2528,KC= 0.2582
Ncalc = 1.44 - 1.45

Optical Data:

Biaxial (-), a=1.426, b=1.453, g=1.456, bire=0.0300, 2V(Calc)=36, 2V(Meas)=38. Dispersion none.

Pleochroism (x):

none.

Calculated Properties of Hexahydrite

Electron Density:

Bulk Density (Electron Density)=1.81 gm/cc
note: Specific Gravity of Hexahydrite =1.72 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Hexahydrite= 1.21 barns/electron
U=PE_Hexahydrite x rElectron Density= 2.19 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Hexahydrite is Not Radioactive

Hexahydrite Classification

Dana Class:

29.06.08.01 (29)Hydrated Acid and Sulfates

(29.06)where A XO4 · x(H2O)

(29.06.08)Hexahydrite Group (Space Group: C2/c)

29.06.08.01 Hexahydrite MgSO4•6(H2O) A2/a 2/m

29.06.08.02 Bianchite (Zn,Fe)(SO4)•6(H2O) C 2/c 2/m

29.06.08.03 Ferrohexahydrite FeSO4•6(H2O) C 2/c 2/m

29.06.08.04 Nickelhexahydrite (Ni,Mg,Fe)(SO4)•6(H2O) C 2/c 2/m

29.06.08.05 Moorhouseite (Co,Ni,Mn)SO4•6(H2O) C 2/c 2/m

29.06.08.06 Chvaleticeite (Mn,Mg)SO4•6(H2O) C 2/c 2/m

Strunz Class:

07.CB.25 07 - SULFATES (SELENATES, TELLURATES)

07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O

07.CB -With only medium-sized cations

07.CB.25 Bianchite (Zn,Fe)(SO4)•6(H2O) C 2/c 2/m

07.CB.25 Ferrohexahydrite FeSO4•6(H2O) C 2/c 2/m

07.CB.25 Chvaleticeite (Mn,Mg)SO4•6(H2O) C 2/c 2/m

07.CB.25 Hexahydrite MgSO4•6(H2O) A2/a 2/m

07.CB.25 Moorhouseite (Co,Ni,Mn)SO4•6(H2O) C 2/c 2/m

07.CB.25 Nickelhexahydrite (Ni,Mg,Fe)(SO4)•6(H2O) C 2/c 2/m

Other Hexahydrite Information

References:

NAME( Mason68) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Hexahydrite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Franklin Minerals(Dunn)
6 - GeoScienceWorld
7 - Google Images
8 - Google Scholar
9 - Handbook of Mineralogy (MinSocAm)
10 - Handbook of Mineralogy (UofA)
11 - MinDAT
12 - Mineralienatlas (Deutsch)
13 - Online Mineral Museum
14 - QUT Mineral Atlas
15 - Ruff.Info
16 - WWW-MINCRYST

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

Hexahydrite

MgSO4•6(H2O)
Dana No: 29.06.08.01 Strunz No: 07.CB.25
Locality:

Notes: