Barstowite Mineral Data

Barstowite Mineral Data +

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General Barstowite Information

Chemical Formula:

Pb4(CO3)Cl6·(H2O)

Composition:

Molecular Weight = 1,119.54 gm

Hydrogen 0.18 % H 1.61 % H₂O

Lead 74.03 % Pb 79.75 % PbO

Carbon 1.07 % C 3.93 % CO₂

Chlorine 19.00 % Cl 19.00 % Cl

- % Cl -4.29 % -O=Cl₂

Oxygen 5.72 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₄(CO₃)Cl₆·(H₂O)

Environment:

Quartz-dolomite ore vein exposed to sea water at the base of the cliff.

IMA Status:

Approved IMA 1991

Locality:

Bounds Cliff, St. Endellion, Cornwall, England. Link to MinDat.org Location Data.

Name Origin:

Named for Richard William Barstow (1947-1982), Cornish mineral dealer.

Synonym:

ICSD 411366

IMA1989-057

PDF 51-1520

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Barstowite Crystallography

Axial Ratios:

a:b:c =0.457:1:1.8113

Cell Dimensions:

a = 4.2043, b = 9.199, c = 16.663, Z = 2; beta = 91.82° V = 644.12 Den(Calc)= 5.77

Crystal System:

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

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

By Intensity(I/I_o): 4.02(1), 2.296(0.8), 2.377(0.6),

Crystal Structure:

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Steele I M , Pluth J J , Stanley C J , Mineralogical Magazine , 63 (1999) p.901-907, Crystal structure of barstowite (3PbCl2PbCO3H2O), Locality: Bounds Cliff, St Endellion, Cornwall

Physical Properties of Barstowite

Cleavage:

[???] Indistinct

Color:

Colorless, White.

Density:

5.5 - 5.69, Average = 5.59

Diaphaniety:

Transparent to Opaque

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

3 - Calcite

Luster:

Adamantine

Streak:

white

Optical Properties of Barstowite

Optical Data:

Biaxial (?)

NCalc= 2.04 - from Gladstone-Dale relationship (KC = 0.1799) where Ncalc=Dcalc*KC+1
NCalc= 2.01 - from Gladstone-Dale relationship (KC = 0.1799) where Ncalc=Dmeas*KC+1

RL Anisotrophism:

Weak to moderate.

RL Bireflectance:

Moderate, gray to dark gray.

RL Color:

White with abundant colorless internal reflections.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Barstowite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	14.20	14.80
420 nm	14.00	14.60
440 nm	13.80	14.40
460 nm	13.70	14.10
480 nm	13.40	13.90
500 nm	13.20	13.70
520 nm	13.10	13.50
540 nm	12.90	13.40
560 nm	12.80	13.20
580 nm	12.70	13.10
600 nm	12.60	13.00
620 nm	12.50	12.90
640 nm	12.50	12.90
660 nm	12.40	12.80
680 nm	12.30	12.80
700 nm	12.30	12.70

**Calculated Relative Intensity Colors of Barstowite in Air**
Relative Intensity	0%	70%	100%	140%	210%	280%	350%	420%	490%	560%	630%	690%
R₁
R₂

Calculated Properties of Barstowite

Electron Density:

r_electron=4.84 gm/cc
note: r_Barstowite=5.77 gm/cc.

Fermion Index

Fermion Index = 0.16375
Boson Index = 0.83625

Photoelectric:

PE_Barstowite=1,354.95 barns/electron
U=PE_Barstowite x r_electron=6,564.29 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Barstowite is Not Radioactive

Barstowite Classification

Dana Class:

12.1.7.1 (12)Compound Halides

(12.1)with miscellaneous anions

(12.1.7)Dana Group

12.1.7.1 Barstowite Pb4(CO3)Cl6·(H2O) P 2₁/m 2/m

Strunz Class:

V/E.08-100 V - Nitrates, Carbonates and Borates

V/E - Water-bearing carbonates with unfamiliar anions

V/E.08 - Strontiodresserite - Dundasite series

V/E.08-05 Thomasclarkite-(Y)! (Na,Ce)(Y,REE)(HCO3)(OH)3·4(H2O) P 2 2

V/E.08-10 Kamphaugite-(Y) Ca(Y,REE)(CO3)2(OH)2·3(H2O) P 4₁2₁2 4 2 2

V/E.08-20 Calcio-ancylite-(Ce) CaCe(CO3)2(OH)·(H2O) P mmm 2/m 2/m 2/m

V/E.08-25 Calcio-ancylite-(Nd) CaNd(CO3)2(OH)·(H2O) Pm m

V/E.08-28 Ancylite-(La)! Sr(La,Ce)(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m

V/E.08-30 Ancylite-(Ce) SrCe(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m

V/E.08-40 Gysinite-(Nd) Pb(Nd,La)(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m

V/E.08-50 Strontiodresserite (Sr,Ca)Al2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m

V/E.08-60 Dresserite BaAl2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m

V/E.08-70 Hydrodresserite BaAl2(CO3)2(OH)4·3(H2O) P1 1

V/E.08-80 Montroyalite Sr4Al8(CO3)3(OH,F)26·10-11(H2O) Unk. Tri

V/E.08-90 Dundasite PbAl2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m

V/E.08-95 Petterdite! PbCr2(CO3)2(OH)4·H2O Pbnm 2/m 2/m 2/m

V/E.08-100 Barstowite Pb4(CO3)Cl6·(H2O) P 2₁/m 2/m

Other Barstowite Information

References:

NAME( Dana8) PHYS. PROP.(AmMin, vol 86) OPTIC PROP.(AntBidBlaNic5)

See Also:

Links to other databases for Barstowite :
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 - WWW-MINCRYST 13 -École des Mines de Paris

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

Barstowite

Pb4(CO3)Cl6·(H2O)
Dana No: 12.1.7.1 Strunz No: V/E.08-100
Locality:

Notes: