Clinoailacamite, a NEW POLYMORPH of Gur(Ohl3cl, and ITS Relaflonship to PARATACAMITE and 'ANARAKITE"*
61. Tlrc Catwdian M ineral ogi st Vol. 34, pp.6lJ2 (1996) CLINOAilACAMITE,A NEW POLYMORPHOF Gur(OHl3Cl, AND ITS RELAflONSHIPTO PARATACAMITEAND 'ANARAKITE"* JOHNL. JAMBOR Department of Earth Sciences, University of Waterlao, Waterloo, Ontario N2L 3GI JOHNE. DUTRZAC CANMET,Deparnnent of Naaral ResourcesCananq 555 Booth Street, Ottawa, Ontaria KIA OGj ANDREW C. ROBERTS GeologicalSurvey of Cananq601 Booth Street, Otawa" Owaria KIA 088 JOELD. GRICE ResearchDivisiou CatadianMuseurn of Naure, Ottatva,Ontaria KIP 6P4 JANT. SZYMA(SKI CANMET,Depamnent of NaturalResources Canad4 555 Booth Street, Ottawo" Ontario KIA 0GI ABSTRA T The new mineral clinoatacamiteis a polmorph of Cu2(OII)3C| othen are botallackite (monoclinic), atacamite(ortho- rhornbic),an{ possiblyparatacamite (rhombohedral). Clinoatacanite is monoclinic, spacegroup P21ln,a 6.157(2),b 6.814Q), c 9.104(5) A, p 99.65(4)", which is transformableto a pseudorhombohedralcell approximating that of paxatacamite. Clinoatacamitehas been found in specimensfrom severallocalities, aad coexistswith paratacamitein the holotype specimenof p,aralacamite.The two minerals are not readily distinguishedexcept by optical and X-ray methods:paratacamite is uniaxial negative, whereasclinoatacamite is biaxht negative, 2V@75(5f . Strongestlines of the X-ray powder paltern of clino- aracamireld n A(D@k[)]are 5.47(100)(T0l,0Ll),2.887(40X121J03),2.767(60)81.1),2.742Q0)(0r3,202),2.266(@)Q20), 2.243(50)(004),and L.7M(5Q82a,040). Clinoatacamiteis readily synthesizedand a seriesof experimentswas conductedto promotethe uptakeof Zn and duplicatethe formula of the dubiousmineral "anarakite" (CuZn)2(OI{)3C1.Generally, products with more than about6 mol%o"7iproved to be hexagonal,i.e., nrcranpaatacamite, as did specimensof "anarakite"fron fhe type locality.
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