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
X Ray Diffraction:	By Intensity(I/Io): 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:	relectron=6.33 gm/cc note: rMereheadite =7.72 gm/cc.
Fermion Index	Fermion Index = 0.18969 Boson Index = 0.81031
Photoelectric:	PEMereheadite =1,606.99 barns/electron U=PEMereheadite x relectron=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 Search for Mereheadite using:   Web webmineral.com [ALTAVISTA] [AOL] [All-The-Web] [HotBot] [Ixquick] [MAMMA] [MSN.COM] [Netscape] [Scirus] [Teoma] [Wikipedia] [YAHOO] Visit our Advertisers for Mereheadite : AA Mineral Specimens B & L Fine Minerals Crystal Vaults Dan Weinrich Fine Minerals Dan Weinrich Auctions e-Rocks Auctions Excalibur Minerals Exceptional Minerals Fabre Minerals Greenside Minerals Heliodor John Betts Fine Minerals Mason's Minerals Mineral News Mineral of the Month Club MineralsWeb Fine Minerals Rockshop.cz T G Fine Minerals Wrights Rock Shop Translate Mereheadite Mineral Data : Ask about Mereheadite here : Ask-A-Mineralogist from the Mineralogical Society of America Mindat.org's Discussion Groups Original Rockhounds Discussion Group Rockhounds Discussion Group on Yahoo Groups Mineral Discussion Forum from Fabre Minerals - also available in Español 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: