Mereheadite Mineral Data

Mereheadite Mineral Data +

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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.

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 - PrismaticH-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

Diaphaniety:

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

Optical Data:

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

Calculated Properties of Mereheadite

Electron Density:

r_electron=6.33 gm/cc
note: r_Mereheadite=7.72 gm/cc.

Fermion Index

Fermion Index = 0.18969
Boson Index = 0.81031

Photoelectric:

PE_Mereheadite=1,606.99 barns/electron
U=PE_Mereheadite x r_electron=10174.33 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Mereheadite is Not Radioactive

Mereheadite Classification

Dana Class:

10.4.5.1 (10)Oxyhalides and Hydroxyhalides

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

(10.4.5)Dana Group

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

Strunz Class:

III/D.11-35 III - Halogenides

III/D - Oxi-halogenides with Pb - Bi - Sb and related compounds

III/D.11 - Mendipite - Onoratoite series

III/D.11-10 Mendipite Pb3Cl2O2 P 2₁2₁2₁ 2 2 2

III/D.11-15 Damaraite Pb3O2(OH)Cl Pmc2 mm2

III/D.11-17 Chubutite* Pb7O6Cl2 Unk Ortho

III/D.11-20 Penfieldite Pb2Cl3(OH) P 6/mmm 6/m 2/m 2/m

III/D.11-30 Blixite Pb2Cl(O,OH)2 Unk Ortho

III/D.11-35 Mereheadite Pb2O(OH)Cl C 2/c 2/m

III/D.11-40 Sundiusite Pb10(SO4)Cl2O8 C 2,Cm,C 2/m Mono

III/D.11-50 Asisite Pb12(SiO4)O8Cl4 I 4/mmm 4/m 2/m 2/m

III/D.11-55 Parkinsonite (Pb,Mo,[])8O8Cl2 I 4/mmm 4/m 2/m 2/m

III/D.11-60 Thorikosite Pb3(Sb,As)O3(OH)Cl2 I 4/mmm 4/m 2/m 2/m

III/D.11-65 Philolithite! Pb12O6Mn(Mg,Mn)2(Mn,Mg)4(SO4)(CO3)4Cl4(OH)12 P 4₁/nnm 4/m 2/m 2/m

III/D.11-70 Pinalite Pb3(WO4)OCl2 Amam 2/m 2/m 2/m

III/D.11-80 Nadorite PbSbO2Cl Bmmb 2/m 2/m 2/m

III/D.11-90 Perite PbBiO2Cl Bmmb 2/m 2/m 2/m

III/D.11-100 Heliophyllite Pb6As2O7Cl4 Unk Ortho

III/D.11-110 Ecdemite Pb6As2O7Cl4 Unk Tetra

III/D.11-120 Onoratoite Sb8O11Cl2 C 2/m 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 -Google Images 4 -Google Scholar 5 -Handbook of Mineralogy (UofA) 6 -MinDAT 7 -MinMax(Deutsch) 8 -MinMax(English) 9 -Mineralienatlas (Deutsch) 10 -QUT Mineral Atlas

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

Mereheadite

Pb2O(OH)Cl
Dana No: 10.4.5.1 Strunz No: III/D.11-35
Locality:

Notes: