Epsomite Mineral Data

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General Epsomite Information

Chemical Formula:

MgSO4•7(H2O)

Composition:

Molecular Weight = 246.48 gm

Magnesium 9.86 % Mg 16.35 % MgO

Hydrogen 5.73 % H 51.16 % H₂O

Sulfur 13.01 % S 32.48 % SO₃

Oxygen 71.40 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg(SO₄)•7(H₂O)

Environment:

White efflorescence on cave walls, volcanic exhalations, or deposited by Mg sulfate spring waters.

IMA Status:

Valid Species (Pre-IMA) 1824

Locality:

Lake-bed deposits on Kruger Mountain, Oregon. Link to MinDat.org Location Data.

Name Origin:

The mineral has long been known from the deposits associated with the mineral waters at Epsom, Surrey, England.

Name Pronunciation:

Epsomite

Synonym:

Bitter Salt

Epsom Salts

ICSD 29384

PDF 36-419

Reichardite - massive

Epsomite Image

Images:

Epsomite

Comments: Pure white compact fibrous mass of epsomite.
Location: Calatayud, Zaragoza, Aragon, Spain. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Epsomite Crystallography

Axial Ratios:

a:b:c =0.9891:1:0.5719

Cell Dimensions:

a = 11.86, b = 11.99, c = 6.858, Z = 4; V = 975.22 Den(Calc)= 1.68

Crystal System:

Orthorhombic - DisphenoidalH-M Symbol (2 2 2) Space Group: P 2₁2₁2₁

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

By Intensity(I/I_o): 4.21(1), 2.677(0.25), 5.35(0.25),

Forms:

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Forms: ( 0 1 0) ( 1 0 1) ( 1 0 0)

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Crystal Structure:

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Baur W H , Acta Crystallographica , 17 (1964) p.1361-1369, On the crystal chemistry of salt hydrates. IV. The refinement of the crystal, structure of MgSO4*7H2O (epsomite), Note: Mg z-coordinate altered in order to reproduce Mg-O bond lengths, Locality: synthetic

Physical Properties of Epsomite

Cleavage:

{010} Perfect, {101} Distinct

Color:

Colorless, White, Yellowish white, Greenish white, Pinkish white.

Density:

1.67 - 1.68, Average = 1.67

Diaphaneity:

Transparent to translucent

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

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 Epsomite

Gladstone-Dale:

CI meas= -0.016 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.013 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2677,KPDmeas= 0.2685,KC= 0.2642
Ncalc = 1.44

Optical Data:

Biaxial (-), a=1.433, b=1.455, g=1.461, bire=0.0280, 2V(Calc)=54, 2V(Meas)=52. Dispersion none.

Pleochroism (x):

none.

Pleochroism (y):

none.

Calculated Properties of Epsomite

Electron Density:

Bulk Density (Electron Density)=1.77 gm/cc
note: Specific Gravity of Epsomite =1.68 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

PE_Epsomite= 1.14 barns/electron
U=PE_Epsomite x rElectron Density= 2.03 barns/cc.

Radioactivity:

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

Epsomite Classification

Dana Class:

29.06.11.01 (29)Hydrated Acid and Sulfates

(29.06)where A XO4 · x(H2O)

(29.06.11)Epsomite Group

29.06.11.01 Epsomite MgSO4•7(H2O) P 2₁2₁2₁ 2 2 2

29.06.11.02 Goslarite ZnSO4•7(H2O) P 2₁2₁2₁ 2 2 2

29.06.11.03 Morenosite NiSO4•7(H2O) P 2₁2₁2₁ 2 2 2

Strunz Class:

07.CB.40 07 - SULFATES (SELENATES, TELLURATES)

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

07.CB -With only medium-sized cations

07.CB.40 Epsomite MgSO4•7(H2O) P 2₁2₁2₁ 2 2 2

07.CB.40 Goslarite ZnSO4•7(H2O) P 2₁2₁2₁ 2 2 2

07.CB.40 Morenosite NiSO4•7(H2O) P 2₁2₁2₁ 2 2 2

Other Epsomite Information

See Also:

Links to other databases for Epsomite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
6 - Franklin Minerals(Dunn)
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineral and Gemstone Kingdom
14 - Mineralienatlas (Deutsch)
15 - NSDL Reciprocal Net (JAVA)
16 - Online Mineral Museum
17 - QUT Mineral Atlas
18 - Ruff.Info
19 - WWW-MINCRYST

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Ask about Epsomite here :
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Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

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

Epsomite

MgSO4•7(H2O)
Dana No: 29.06.11.01 Strunz No: 07.CB.40
Locality:

Notes: