vauquelinite

{{Short description|Complex mineral}}

{{Infobox mineral

| name = Vauquelinite

| image = Vauquelinite-120513.jpg

| imagesize = 260px

| alt =

| caption =

| category = Phosphate mineral

| formula = CuPb₂(CrO₄)(PO₄)(OH)

| IMAsymbol = Vql{{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 = 7.FC.05

| system = Monoclinic

| class = Prismatic (2/m)
(same H-M symbol)

| symmetry = P2₁/n

| unit cell = a = 13.754(5) Å, b = 5.806(6) Å
c = 9.563(3) Å; β = 94.55°; Z = 4

| color = Olive-green, apple-green, brown to nearly black

| colour =

| habit = Irregular wedge shaped crystals, mammillary, reniform masses

| twinning = Present on {102}

| cleavage = Indistinct

| fracture = Irregular

| tenacity = Brittle

| mohs = 2.5 – 3

| luster = Adamantine, resinous

| streak = Greenish or brownish

| diaphaneity = Translucent

| gravity = 6.16

| density =

| polish =

| opticalprop = Biaxial (−)

| refractive = n_α = 2.110 n_β = 2.220 n_γ = 2.220

| birefringence = δ = 0.110

| pleochroism = X = Light green, Y = Light brown, Z = Light brown

| 2V = Near zero

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| references = [http://www.mindat.org/min-4163.html Mindat – Vauquelinite][http://webmineral.com/data/Vauquelinite.shtml Webmineral – Vauquelinite][http://www.handbookofmineralogy.com/pdfs/vauquelinite.pdf Handbook of Mineralogy – Vauquelinite]

}}

Vauquelinite is a complex mineral with the formula CuPb₂(CrO₄)(PO₄)(OH) making it a combined chromate and phosphate of copper and lead. It forms a series with the arsenate mineral fornacite.

It was first described in 1818 in the Beryozovskoye deposit, Urals, Russia, and named for Louis Vauquelin (1763–1829), a French chemist. It occurs in oxidized hydrothermal ore deposits and is associated with crocoite, pyromorphite, mimetite, cerussite, beudantite and duftite at the type locality in Russia.