tlapallite

{{Short description|Rare and complex tellurate mineral}}

{{Infobox mineral

| name = Tlapallite

| boxwidth =

| boxbgcolor =

| image =Tlapallite.jpg

| imagesize =

| alt =

| caption =Tlapallite on matrix from Bambollita mine (La Oriental), Moctezuma, Municipio de Moctezuma, Sonora, Mexico. Picture width: 29 mm

| category = Tellurate minerals

| formula = {{chem2|(Ca,Pb)3CaCu6[Te(4+)3Te(6+)O12]2(Te(4+)O3)2(SO4)2*3H2O}}

| IMAsymbol = Tpl{{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 =

| strunz = 4.JL.25

| dana = 34.8.2.1

| system = Monoclinic
P3 2 1

| symmetry =

| unit cell = a = 11.97 Å, b = 9.11 Å
c = 15.66 Å; Z = 4

| color = Green

| colour =

| habit = Thin crusts or botryoidal aggregates

| class =

| twinning =

| cleavage = None

| fracture =

| tenacity =

| mohs = 3

| luster =Vitreous, Waxy

| streak =Pale green

| diaphaneity =Translucent

| gravity =5.38 (measured)

5.05–5.465 (calculated)

| density =

| polish =

| opticalprop =Biaxial (−)

| refractive =n_α = 1.815 – 1.915 n_β = 1.960 – 2.115 n_γ = 1.960 – 2.115

| birefringence =δ = 0.1450–0.2000

| pleochroism =Moderate, different shades of green

| 2V =0

| dispersion =

| extinction =

| length fast/slow =

| fluorescence =None

| absorption =

| melt =

| fusibility =Fuses readily

| diagnostic =Thin green paint-like crusts

| solubility =Soluble in cold HCl

Slightly soluble in HNO₃ unless heated

| impurities =

| alteration =

| other =

| prop1 =

| prop1text =

| references ={{ref|1}}{{ref|2}}{{ref|3}}{{ref|4}}

| var1 =

| var1text =

| var2 =

| var2text =

| var3 =

| var3text =

| var4 =

| var4text =

| var5 =

| var5text =

| var6 =

| var6text =

}}

Tlapallite is a rare and complex tellurate mineral with the chemical formula {{chem2|(Ca,Pb)3CaCu6[Te(4+)3Te(6+)O12]2(Te(4+)O3)2(SO4)2*3H2O}}. It has a Moh's hardness of 3 and it is green in colour. It was named after the Nahua word "Tlalpalli", which translates to paint, referring to the paint-like habit of the mineral. Its formula and crystal structure were redefined in 2019, showing it contained a mixed-valence phyllotellurate layer {{chem2|[Te(4+)3Te(6+)O12](12-)}}.{{Cite journal|last1=Missen|first1=Owen P.|last2=Kampf|first2=Anthony R.|last3=Mills|first3=Stuart J.|last4=Housley|first4=Robert M.|last5=Spratt|first5=John|last6=Welch|first6=Mark D.|last7=Coolbaugh|first7=Mark F.|last8=Marty|first8=Joe|last9=Chorazewicz|first9=Marek|last10=Ferraris|first10=Cristiano|date=2019|title=The crystal structures of the mixed-valence tellurium oxysalts tlapallite}}, {{chem2|(Ca,Pb)3CaCu6[Te(4+)3Te(6+)O12]2(Te(4+)O3)2(SO4)2·3H2O}}, and carlfriesite, {{chem2|CaTe(4+)2Te(6+)O8}}{{cite journal|url=https://www.cambridge.org/core/journals/mineralogical-magazine/article/abs/crystal-structures-of-the-mixedvalence-tellurium-oxysalts-tlapallite-capb3cacu6te43te6o122te4o32so423h2o-and-carlfriesite-cate42te6o8/52763FBB654B9FD2C7AC19D0F3DDC833|journal=Mineralogical Magazine|language=en|volume=83|issue=4|pages=539–549|doi=10.1180/mgm.2019.9|s2cid=135390072|issn=0026-461X|title=The crystal structures of the mixed-valence tellurium oxysalts tlapallite, (Ca,Pb)3CaCu6[Te4+3Te6+O12]2(Te4+O3)2(SO4)2·3H2O, and carlfriesite, CaTe4+2Te6+O8|year=2019|last1=Missen|first1=Owen P.|last2=Kampf|first2=Anthony R.|last3=Mills|first3=Stuart J.|last4=Housley|first4=Robert M.|last5=Spratt|first5=John|last6=Welch|first6=Mark D.|last7=Coolbaugh|first7=Mark F.|last8=Marty|first8=Joe|last9=Chorazewicz|first9=Marek|last10=Ferraris|first10=Cristiano|bibcode=2019MinM...83..539M|url-access=subscription}}