Paratacamite

{{Short description|Mineral in the halide minerals category}}

{{Infobox mineral

| name = Paratacamite

| category = Halide mineral

| boxwidth =

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| image = Paratacamite-231241.jpg

| imagesize = 260px

| caption = Paratacamite from Cornwall, England

| formula = {{chem2|Cu3(Cu,Zn)(OH)6Cl2}}

| IMAsymbol = Pata{{Cite journal|last=Warr|first=L.N.|date=2021|title=IMA–CNMNC approved mineral symbols|journal=Mineralogical Magazine|volume=85|issue=3 |pages=291–320|doi=10.1180/mgm.2021.43 |bibcode=2021MinM...85..291W |s2cid=235729616 |doi-access=free}}

| molweight = 58.433 g/mol

| strunz = III / D.01-55

| system = Trigonal

| class = Rhombohedral

| symmetry =

| unit cell = a = 13,654, c = 14,041;

| color = Green

| habit =

| twinning =

| cleavage = Very good

| fracture = Conchoidal

| tenacity =

| mohs = 3

| luster = Vitreous

| refractive =

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| pleochroism =

| streak = Green

| gravity = 3.74

| density = 3.74g/cm³

| melt =

| fusibility =

| diagnostic =

| solubility = Acid-soluble

| diaphaneity = Transparent

| other =

| references = {{cite web|url=https://www.mindat.org/min-3115.html|website=mindat.org|title=Paratacamite: Paratacamite mineral information and data.|accessdate=2017-09-20}}

}}

Paratacamite is a mineral in the halide minerals category. Its chemical formula is {{chem2|Cu3(Cu,Zn)(OH)6Cl2}}. Its name is derived from its association with atacamite. Paratacamite was first described by Herbert Smith in 1906.{{cite journal|last1=Smith|first1=G.F.H.|last2=Prior|first2=G.T.|year=1906|title=Paratacamite, a new oxychloride of copper|journal=Mineralogical Magazine|volume=14|issue=65 |pages=170–177|doi=10.1180/minmag.1906.014.65.09 |bibcode=1906MinM...14..170S }} The zincian endmember {{chem2|Cu3(Zn)(OH)6Cl2}} is called herbertsmithite, and paratacamite is polymorphous with botallackite and atacamite.{{cite journal|last1=Braithwaite |first1=RSW|last2=Mereiter|first2=K|last3=Paar|first3=WH|last4=Clark|first4=AM|year=1004|title=Herbertsmithite, Cu3Zn(OH)6Cl2, a new species, and the definition of paratacamite|journal=Mineralogical Magazine|volume=68|issue=3 |pages=527–539|url=https://rruff.geo.arizona.edu/doclib/mm/vol68/MM68_527.pdf|doi=10.1180/0026461046830204}}

It has been found in Chile, Botallack Mine in Cornwall, Broken Hill, Australia, and in Italy at Capo Calamita on the island of Elba.