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Barstowite Mineral Data
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General Barstowite Information
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 Chemical Formula: |
Pb4(CO3)Cl6•(H2O) |
| Composition: |
Molecular Weight = 1,119.54 gm |
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Hydrogen 0.18 % H 1.61 % H2O |
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Lead 74.03 % Pb 79.75 % PbO |
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Carbon 1.07 % C 3.93 % CO2 |
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Chlorine 19.00 % Cl 19.00 % Cl |
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- %
Cl -4.29 % -O=Cl2 |
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Oxygen 5.72 % O |
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______ ______ |
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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. |
| Name Pronunciation: |
Barstowite + Pronunciation  |
| Synonym: |
ICSD 411366 |
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IMA1989-057 |
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PDF 51-1520 |
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Barstowite Image |
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Images:
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Barstowite
Comments: SEM images of irregular prismatic barstowite with phosgenite. (MinMag, v55:378).
Location: Lead-antimony vein at the southwestern end of Bounds Cliff, St Endellion, Cornwall, UK.
Scale: Scale bar left 400 µm right 100 µm.
© Mineralogical Magazine |
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Barstowite Crystallography
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| 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 - Prismatic H-M Symbol (2/m) Space Group: P 21/m |
| X Ray Diffraction: |
By Intensity(I/Io): 4.02(1), 2.296(0.8), 2.377(0.6), |
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Physical Properties of Barstowite
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| Cleavage: |
{???} Indistinct |
| Color: |
Colorless, White. |
| Density: |
5.5 - 5.69, Average = 5.59 |
| Diaphaneity: |
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 |
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Optical Properties of Barstowite
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| Optical Data: |
Biaxial (?) |
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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
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| 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 |
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∑ R1(λ) |
∑ R2(λ) |
| 400 nm |
14.20 |
14.80 |
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| 420 nm |
14.00 |
14.60 |
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| 440 nm |
13.80 |
14.40 |
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| 460 nm |
13.70 |
14.10 |
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| 480 nm |
13.40 |
13.90 |
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| 500 nm |
13.20 |
13.70 |
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| 520 nm |
13.10 |
13.50 |
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| 540 nm |
12.90 |
13.40 |
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| 560 nm |
12.80 |
13.20 |
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| 580 nm |
12.70 |
13.10 |
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| 600 nm |
12.60 |
13.00 |
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| 620 nm |
12.50 |
12.90 |
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| 640 nm |
12.50 |
12.90 |
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| 660 nm |
12.40 |
12.80 |
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| 680 nm |
12.30 |
12.80 |
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| 700 nm |
12.30 |
12.70 |
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Calculated Relative Intensity Colors of Barstowite in Air
Relative
Intensity |
0% |
70% |
100% |
140% |
210% |
280% |
350% |
420% |
490% |
560% |
630% |
690% |
| R1 |
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| R2 |
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Calculated Properties of Barstowite
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| Electron Density: |
Bulk Density (Electron Density)=4.84 gm/cc
note: Specific Gravity of Barstowite =5.77 gm/cc.
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| Fermion Index: |
Fermion Index = 0.16
Boson Index = 0.84 |
| Photoelectric: |
PEBarstowite =1,354.95 barns/electron
U=PEBarstowite x rElectron Density=6,564.29 barns/cc.
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| Radioactivity: |
GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Barstowite is Not Radioactive |
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Barstowite Classification
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| Dana Class: |
12.01.07.01 (12)Compound Halides |
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(12.01)with miscellaneous anions |
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(12.01.07)Dana Group |
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12.01.07.01 Barstowite Pb4(CO3)Cl6•(H2O) P 21/m 2/m |
| Strunz Class: |
03.DC.95 03 - HALIDES |
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03.D - Oxyhalides, Hydroxyhalides and Related Double Halides |
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03.DC -With Pb (As,Sb,Bi), without Cu |
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03.DC.95 Barstowite Pb4(CO3)Cl6•(H2O) P 21/m 2/m |
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Other Barstowite Information
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| 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 - 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
15 - WWW-MINCRYST
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Barstowite
Pb4(CO3)Cl6•(H2O)
Dana No: 12.01.07.01 Strunz No: 03.DC.95
Locality:
Notes:
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