Mereheadite Mineral Data

General Mereheadite Information

Chemical Formula:

Pb2O(OH)Cl

Composition:

Molecular Weight = 482.86 gm

Hydrogen 0.21 % H 1.87 % H₂O

Lead 85.82 % Pb 92.45 % PbO

Chlorine 7.34 % Cl 7.34 % Cl

- % Cl -1.66 % -O=Cl₂

Oxygen 6.63 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Pb₂O(OH)Cl

Environment:

In lenses and cavities in veins of manganese and iron minerals which cut dolomitic limestones. Related to litharge.

IMA Status:

Approved IMA 1998 (Dana # Added)

Locality:

Merehead Quarry, Cranmore, Somerset, England, U.K. Link to MinDat.org Location Data.

Name Origin:

Named after its locality.

Name Pronunciation:

Mereheadite + Pronunciation

Synonym:

IMA1996-045

Mereheadite Image

Images:

Mereheadite

Comments: Yellowish crystals of mereheadite to 1mm embedded in matrix.
Location: Merehead quarry, Shepton Mallet, Somerset, England. Scale: Picture size 5 mm.
© Tom Loomis / Dakota Matrix

Mereheadite Crystallography

Axial Ratios:

a:b:c =1.0206:1:2.3617

Cell Dimensions:

a = 5.68, b = 5.565, c = 13.143, Z = 4; beta = 90.64° V = 415.41 Den(Calc)= 7.72

Crystal System:

Monoclinic - Prismatic H-M Symbol (2/m) Space Group: C 2/c

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

By Intensity(I/I_o): 2.93(1), 3.785(0.5), 2.825(0.4),

Physical Properties of Mereheadite

Cleavage:

{001} Perfect

Color:

Pale yellow, Reddish orange.

Density:

7.12 - 7.69, Average = 7.4

Diaphaneity:

Translucent

Fracture:

Conchoidal - Uneven - Uneven fracture producing small, conchoidal fragments.

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Hardness:

3.5 - Copper Penny

Luster:

Vitreous - Resinous

Streak:

white

Optical Properties of Mereheadite

Gladstone-Dale:

CI meas= -0.094 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= -0.049 (Good) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.16,KPDmeas= 0.1668,KC= 0.1525
Ncalc = 2.09 - 2.18

Optical Data:

Biaxial (?), a=2.19, g=2.28, bire=0.0900

Calculated Properties of Mereheadite

Electron Density:

Bulk Density (Electron Density)=6.33 gm/cc
note: Specific Gravity of Mereheadite =7.72 gm/cc.

Fermion Index:

Fermion Index = 0.18
Boson Index = 0.82

Photoelectric:

PE_Mereheadite=1,606.99 barns/electron
U=PE_Mereheadite x rElectron Density=10174.34 barns/cc.

Radioactivity:

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

Mereheadite Classification

Dana Class:

10.04.05.01 (10)Oxyhalides and Hydroxyhalides

(10.04)where (A)2 (O,OH) Xq

(10.04.05)Dana Group

10.04.05.01 Mereheadite! Pb2O(OH)Cl C 2/c 2/m

Strunz Class:

03.DC.45 03 - HALIDES

03.D - Oxyhalides, Hydroxyhalides and Related Double Halides

03.DC -With Pb (As,Sb,Bi), without Cu

03.DC.45 Mereheadite! Pb2O(OH)Cl C 2/c 2/m

Other Mereheadite Information

References:

NAME( MinRec) PHYS. PROP.(Min.Mag.,Vol.63,p387-393,1998) OPTIC PROP.(Min.Mag.,Vol.63,p387-393,1998)

See Also:

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

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

Mereheadite

Pb2O(OH)Cl
Dana No: 10.04.05.01 Strunz No: 03.DC.45
Locality:

Notes:

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