walfordite

{{Short description|Tellurite mineral}}

{{Infobox mineral

| name = Walfordite

| image = Walfordite - Tambo Mine, Elqui Province, Coquimbo Region, Chile2.jpg

| alt =

| caption = Walfordite from Tambo Mine, Elqui Province, Chile

| category = Tellurite minerals

| formula = Fe³⁺,Te⁶⁺Te⁴⁺₃O₈

| IMAsymbol = wfd{{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}}

| strunz = 4.JK.05

| dana =

| system = Isometric

| symmetry = I2, Ia3

| unit cell = a = 11.011 Å ; Z = 8

| color =

| colour = Orange

| habit = Microscopic cubic crystals

| twinning =

| cleavage = None

| fracture =

| tenacity = Brittle

| mohs =

| luster = Adamantine

| streak = Orange-yellow

| diaphaneity = Opaque

| gravity = 5.841 (calculated)

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| opticalprop = Isotropic

| refractive = n = 2.23

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| references = [http://rruff.info/doclib/hom/walfordite.pdf Walfordite in the Handbook of Mineralogy][http://www.mindat.org/show.php?id=7360 Walfordite on Mindat.org][http://www.webmineral.com/data/Walfordite.shtml#.Us6pFNLjVVY Walfordite data on Webmineral]

}}

Walfordite is a very rare tellurite mineral that was discovered in Chile in 1999.

{{Cite journal |url=http://rruff.geo.arizona.edu/doclib/cm/vol37/CM37_1261.pdf |title=Walfordite, a New Tellurite Species from the Wendy Open Pit, El Indio - Tambo Mining Property, Chile |journal=The Canadian Mineralogist |volume=37|pages=1261–1268|year=1999 |first1=Malcolm E.|last1=Back |first2=Joel D.|last2=Grice |first3=Robert A.|last3=Gault |first4=Alan J.|last4=Criddle |first5=Joseph A.|last5=Mandarino}} The mineral is described as orange with orange-yellow streak, and is determined to have a chemical formula of Fe³⁺,Te⁶⁺Te⁴⁺₃O₈ with minor titanium and magnesium substitution resulting in an approximate empirical formula of (Fe³⁺,Te⁶⁺,Ti⁴⁺,Mg)(Te⁴⁺)₃O₈.