Picromerite Mineral Data

General Picromerite Information

Chemical Formula:

K2Mg(SO4)2•6(H2O)

Composition:

Molecular Weight = 402.72 gm

Potassium 19.42 % K 23.39 % K₂O

Magnesium 6.04 % Mg 10.01 % MgO

Hydrogen 3.00 % H 26.84 % H₂O

Sulfur 15.92 % S 39.76 % SO₃

Oxygen 55.62 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

K₂Mg(SO₄)₂•6(H₂O)

Environment:

Volcanic fumaroles and marine evaporite deposits.

IMA Status:

Valid Species (Pre-IMA) 1855

Locality:

Vesuvius, Italy Link to MinDat.org Location Data.

Name Origin:

From the Greek for "bitter" and "part" in allusion to the magnesium content which makes this water-soluble salt bitter to the taste.

Name Pronunciation:

Picromerite + Pronunciation

Synonym:

ICSD 26772

PDF 21-1400

Schoenite

Picromerite Image

Images:

Picromerite

Comments: Blocky white picromerite crystals on reddish halite.
Location: Heringen, Werra Valley, North Hesse, Hesse, Germany. Scale: Specimen Size 5.5 x 4.7 x 3.4 cm.
© Rob Lavinsky

Picromerite Crystallography

Axial Ratios:

a:b:c =0.7395:1:0.4987

Cell Dimensions:

a = 9.064, b = 12.256, c = 6.113, Z = 2; beta = 104.8° V = 656.55 Den(Calc)= 2.04

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/a

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

By Intensity(I/I_o): 3.706(1), 4.064(0.95), 4.156(0.85),

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Forms: ( 0 1 1) ( 1 1 1) ( 0 1 0) ( 2 0 1) ( 1 1 0) ( 1 0 0) ( 0 0 1)

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Crystal Structure:

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Kannan K K , Viswamitra M A , Zeitschrift fur Kristallographie , 122 (1965) p.161-174, Crystal structure of magnesium potassium sulfate hexahydrate MgK2(SO4)2*6(H2O), Locality: synthetic

Physical Properties of Picromerite

Cleavage:

{201} Perfect

Color:

Colorless, Gray, Yellow, White, Reddish.

Density:

2.028

Diaphaneity:

Transparent

Habit:

Massive - Granular - Common texture observed in granite and other igneous rock.

Hardness:

2.5 - Finger Nail

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Picromerite

Gladstone-Dale:

CI meas= -0.011 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.005 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2286,KPDmeas= 0.23,KC= 0.2275
Ncalc = 1.46

Optical Data:

Biaxial (+), a=1.4607, b=1.4629, g=1.4755, bire=0.0148, 2V(Calc)=46, 2V(Meas)=47.9.

Calculated Properties of Picromerite

Electron Density:

Bulk Density (Electron Density)=2.09 gm/cc
note: Specific Gravity of Picromerite =2.04 gm/cc.

Fermion Index:

Fermion Index = 0.0075243351
Boson Index = 0.9924756649

Photoelectric:

PE_Picromerite= 3.04 barns/electron
U=PE_Picromerite x r_electron= 6.35 barns/cc.

Radioactivity:

GRapi = 286.60 (Gamma Ray American Petroleum Institute Units)
Concentration of Picromerite per GRapi unit = 0.35 (%)

Estimated Radioactivity from Picromerite - barely detectable

Picromerite Classification

Dana Class:

29.03.06.01 (29)Hydrated Acid and Sulfates

(29.03)where (A+)2 B (XO4)2 · x(H2O)

(29.03.06)Dana Group

29.03.06.01 Picromerite K2Mg(SO4)2•6(H2O) P 2₁/a 2/m

29.03.06.02 Cyanochroite K2Cu(SO4)2•6(H2O) P 2₁/a 2/m

Strunz Class:

07.CC.60 07 - SULFATES (SELENATES, TELLURATES)

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

07.CC -With medium-sized and large cations

07.CC.60 Boussingaultite (NH4)2Mg(SO4)2•6(H2O) P 2₁/a 2/m

07.CC.60 Cyanochroite K2Cu(SO4)2•6(H2O) P 2₁/a 2/m

07.CC.60 Mohrite (NH4)2Fe(SO4)2•6(H2O) P 2₁/c 2/m

07.CC.60 Picromerite K2Mg(SO4)2•6(H2O) P 2₁/a 2/m

07.CC.60 Nickelboussingaultite (NH4)2(Ni,Mg)(SO4)2•6(H2O) P 2₁/a 2/m

Other Picromerite Information

References:

NAME( Dana7) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

Links to other databases for Picromerite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - EUROmin Project
5 - Ecole des Mines de Paris
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

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Ask about Picromerite here :
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Print or Cut-and-Paste your Picromerite Specimen Label here :

Picromerite

K2Mg(SO4)2•6(H2O)
Dana No: 29.03.06.01 Strunz No: 07.CC.60
Locality:

Notes: