Pokrovskite Mineral Data

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)

IMA Status:

Approved IMA 1984

Locality:

Link to MinDat.org Location Data.

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),

Physical Properties of Pokrovskite

Cleavage:

[???] Perfect

Color:

Beige yellow, White, Pink.

Density:

2.51 - 2.52, Average = 2.51

Diaphaniety:

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

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:

r_electron=2.62 gm/cc
note: r_Pokrovskite=2.58 gm/cc.

Fermion Index

Fermion Index = 0.0332
Boson Index = 0.9668

Photoelectric:

PE_Pokrovskite= 0.87 barns/electron
U=PE_Pokrovskite x r_electron= 2.27 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pokrovskite is Not Radioactive

Pokrovskite Classification

Dana Class:

16a.3.2.3 (16a)Carbonates - Hydroxyl or Halogen

(16a.3)where (A B)2 (XO3) Zq

(16a.3.2)Malachite Group

16a.3.2.1 Malachite Cu2(CO3)(OH)2 P 2₁/a 2/m

16a.3.2.2 Nullaginite Ni2(CO3)(OH)2 P 2₁/m,P 2₁ Mono

16a.3.2.3 Pokrovskite Mg2(CO3)(OH)2·0.5(H2O) P 2₁/a 2/m

Strunz Class:

V/C.01-30 V - Nitrates, Carbonates and Borates

V/C - Waterfree carbonates with unfamiliar anions

V/C.01 - Azurite - Rosasite group and related compounds

V/C.01-10 Azurite Cu3(CO3)2(OH)2 P 2₁/a 2/m

V/C.01-20 Malachite Cu2(CO3)(OH)2 P 2₁/a 2/m

V/C.01-25 Georgeite Cu5(CO3)3(OH)4·6(H2O) None

V/C.01-30 Pokrovskite Mg2(CO3)(OH)2·0.5(H2O) P 2₁/a 2/m

V/C.01-40 Mcguinnessite (Mg,Cu)2(CO3)(OH)2 P 2/a or P 2₁/a 2/m

V/C.01-50 Kolwezite (Cu,Co)2(CO3)(OH)2 P1 or P1 Tri

V/C.01-60 Glaukosphaerite (Cu,Ni)2(CO3)(OH)2 P 2₁/a 2/m

V/C.01-70 Nullaginite Ni2(CO3)(OH)2 P 2₁/m,P 2₁ Mono

V/C.01-80 Rosasite (Cu,Zn)2(CO3)(OH)2 P 2₁/a 2/m

V/C.01-90 Zincrosasite (Zn,Cu)2(CO3)(OH)2 P 2₁/a 2/m

V/C.01-100 Hydrozincite Zn5(CO3)2(OH)6 C 2/m 2/m

V/C.01-105 Brianyoungite Zn3(CO3,SO4)(OH)4 C 2/m 2/m

V/C.01-110 Aurichalcite (Zn,Cu)5(CO3)2(OH)6 P 2₁/m 2/m

V/C.01-120 Loseyite (Mn,Zn)7(CO3)2(OH)10 A2/a 2/m

V/C.01-130 Sclarite (Zn,Mg,Mn)4Zn3(CO3)2(OH)10 A2/a 2/m

Other Pokrovskite Information

References:

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 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (UofA) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas 12 -École des Mines de Paris

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Pokrovskite

Mg2(CO3)(OH)2·0.5(H2O)
Dana No: 16a.3.2.3 Strunz No: V/C.01-30
Locality:

Notes: