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. |
Synonym: |
ICSD 411366 |
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IMA1989-057 |
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PDF 51-1520 |
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Search for Barstowite Images |
Images:
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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 - PrismaticH-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), |
Crystal Structure:
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drag2 - RMB Resize/Rotate
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Help on Above
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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
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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 |
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 |
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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 |
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: |
relectron=4.84 gm/cc note: rBarstowite =5.77 gm/cc. |
Fermion Index |
Fermion Index = 0.16375 Boson Index = 0.83625 |
Photoelectric: |
PEBarstowite =1,354.95 barns/electron U=PEBarstowite x relectron=6,564.29 barns/cc. |
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: |
12.1.7.1 (12)Compound Halides |
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(12.1)with miscellaneous anions |
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(12.1.7)Dana Group |
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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 |
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V/E - Water-bearing carbonates with unfamiliar anions |
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V/E.08 - Strontiodresserite - Dundasite series |
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V/E.08-05 Thomasclarkite-(Y)! (Na,Ce)(Y,REE)(HCO3)(OH)3·4(H2O) P 2 2 |
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V/E.08-10 Kamphaugite-(Y) Ca(Y,REE)(CO3)2(OH)2·3(H2O) P 41212 4 2 2 |
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V/E.08-20 Calcio-ancylite-(Ce) CaCe(CO3)2(OH)·(H2O) P mmm 2/m 2/m 2/m |
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V/E.08-25 Calcio-ancylite-(Nd) CaNd(CO3)2(OH)·(H2O) Pm m |
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V/E.08-28 Ancylite-(La)! Sr(La,Ce)(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m |
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V/E.08-30 Ancylite-(Ce) SrCe(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m |
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V/E.08-40 Gysinite-(Nd) Pb(Nd,La)(CO3)2(OH)·(H2O) Pmcn 2/m 2/m 2/m |
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V/E.08-50 Strontiodresserite (Sr,Ca)Al2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m |
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V/E.08-60 Dresserite BaAl2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m |
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V/E.08-70 Hydrodresserite BaAl2(CO3)2(OH)4·3(H2O) P1 1 |
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V/E.08-80 Montroyalite Sr4Al8(CO3)3(OH,F)26·10-11(H2O) Unk. Tri |
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V/E.08-90 Dundasite PbAl2(CO3)2(OH)4·(H2O) Pbmm 2/m 2/m 2/m |
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V/E.08-95 Petterdite! PbCr2(CO3)2(OH)4·H2O Pbnm 2/m 2/m 2/m |
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V/E.08-100 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 -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 :
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Barstowite
Pb4(CO3)Cl6·(H2O)
Dana No: 12.1.7.1 Strunz No: V/E.08-100
Locality:
Notes:
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