Pokrovskite Mineral Data

General Pokrovskite Information

Chemical Formula:

Mg2(CO3)(OH)2•0.5(H2O)

Composition:

Molecular Weight = 151.64 gm

Magnesium 32.06 % Mg 53.16 % MgO

Hydrogen 1.99 % H 17.82 % H₂O

Carbon 7.92 % C 29.02 % CO₂

Oxygen 58.03 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₂(CO₃)(OH)₂•0.5(H₂O)

Environment:

Ultramafic bodies of dunite or serpentinite.

IMA Status:

Approved IMA 1984

Locality:

Drillhole in the Zlatogorsk massif, 90 km west-southwest of Kokchetav, Kazakhstan. Link to MinDat.org Location Data.

Name Origin:

Named for Pavel Vladimirovich Pokrovskii (1912-1979), Russian mineralogist, Institute of Geology and Geochemistry, Sverdlovsk, Russia.

Name Pronunciation:

Pokrovskite + Pronunciation

Pokrovskite Image

Images:

Pokrovskite Hydromagnesite

Comments: Tan spherical pokrovskite on serpentinite rock with white hydromagnesite sprays.
Location: KCA Quarry, San Benito County, California, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Pokrovskite Crystallography

Axial Ratios:

a:b:c =0.7685:1:0.2766

Cell Dimensions:

a = 9.43, b = 12.27, c = 3.395, Z = 4; beta = 96.6° V = 390.22 Den(Calc)= 2.58

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): 2.6(1), 2.17(0.9), 6.1(0.7),

Crystal Structure:

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drag2 - RMB Resize/Rotate
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H - Help Screen
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Help on Above

Perchiazzi N , Merlino S , European Journal of Mineralogy , 18 (2006) p.787-792, The malachite-rosasite group: crystal structures of glaukosphaerite and, pokrovskite

Physical Properties of Pokrovskite

Cleavage:

{???} Perfect

Color:

Beige yellow, White, Pink.

Density:

2.51 - 2.52, Average = 2.51

Diaphaneity:

Transparent to Translucent

Hardness:

3 - Calcite

Luster:

Earthy (Dull)

Streak:

white

Optical Properties of Pokrovskite

Gladstone-Dale:

CI meas= -0.027 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.001 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2283,KPDmeas= 0.2342,KC= 0.2281
Ncalc = 1.57 - 1.59

Optical Data:

Biaxial (-), a=1.537, b=1.611, g=1.619, bire=0.0820, 2V(Calc)=34, 2V(Meas)=18.

Calculated Properties of Pokrovskite

Electron Density:

Bulk Density (Electron Density)=2.62 gm/cc
note: Specific Gravity of Pokrovskite =2.58 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_Pokrovskite= 0.87 barns/electron
U=PE_Pokrovskite x rElectron Density= 2.27 barns/cc.

Radioactivity:

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

Pokrovskite Classification

Dana Class:

16a.03.02.03 (16a)Carbonates - Hydroxyl or Halogen

(16a.03)where (A B)2 (XO3) Zq

(16a.03.02)Malachite Group

16a.03.02.01 Malachite Cu2(CO3)(OH)2 P 2₁/a 2/m

16a.03.02.02 Nullaginite Ni2(CO3)(OH)2 P 2₁/m,P 2₁ Mono

16a.03.02.03 Pokrovskite Mg2(CO3)(OH)2•0.5(H2O) P 2₁/a 2/m

16a.03.02.04 Chukanovite! Fe2(CO3)(OH)2 P 2₁/a 2/m

Strunz Class:

05.BA.10 05 - CARBONATES (NITRATES)

05.B - Carbonates with additional anions, without H2O

05.BA -With Cu, Co, Ni, Zn, Mg, Mn

05.BA.10 Nullaginite Ni2(CO3)(OH)2 P 2₁/m,P 2₁ Mono

05.BA.10 Georgeite Cu5(CO3)3(OH)4•6(H2O) None

05.BA.10 Malachite Cu2(CO3)(OH)2 P 2₁/a 2/m

05.BA.10 Glaukosphaerite (Cu,Ni)2(CO3)(OH)2 P 2₁/a 2/m

05.BA.10 Mcguinnessite (Mg,Cu)2(CO3)(OH)2 P 2/a or P 2₁/a 2/m

05.BA.10 Kolwezite (Cu,Co)2(CO3)(OH)2 P1 or P1 Tri

05.BA.10 Pokrovskite Mg2(CO3)(OH)2•0.5(H2O) P 2₁/a 2/m

05.BA.10 Rosasite (Cu,Zn)2(CO3)(OH)2 P 2₁/a 2/m

05.BA.10 Zincrosasite (Zn,Cu)2(CO3)(OH)2 P 2₁/a 2/m

05.BA.10 Chukanovite! Fe2(CO3)(OH)2 P 2₁/a 2/m

Other Pokrovskite Information

References:

NAME( AntBidBlaNic3) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)

See Also:

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

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Ask about Pokrovskite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
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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 Pokrovskite Specimen Label here :

Pokrovskite

Mg2(CO3)(OH)2•0.5(H2O)
Dana No: 16a.03.02.03 Strunz No: 05.BA.10
Locality:

Notes: