Corkite

{{Short description|Phosphate mineral}}

{{Infobox mineral

| name = Corkite

| category = Phosphate minerals

| boxwidth = 24

| boxbgcolor =

| image = Corkite-Goethite.jpg

| caption = Corkite on a goethite matrix

| formula = PbFe₃[(OH)₆:SO₄:PO₄]

| IMAsymbol = Cok{{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 = 667.82 g/mol

| strunz = 8.BL.05

| dana = 43.4.1.2

| system = Trigonal

| class = Ditrigonal pyramidal (3/m)
(same H-M symbol)

| symmetry = R3m

| unit cell = a = 7.3065(5) Å,
c = 16.897(2) Å;
V = 781.2 Å³; Z = 3

| color = Brown to light yellowish brown, pale yellow, yellowish green to dark green

| habit = Crystals pseudocubic rhombohedral with prominent {10{{overline|1}}1}. Commonly in crusts and massive

| lattice =

| twinning =

| cleavage = Perfect on {0001}

| fracture =

| tenacity =

| mohs = 3.5–4.5

| luster = Vitreous, resinous

| refractive = n_ω = 1.930 n_ε = 1.930 n = 1.93 – 1.96

| opticalprop = Uniaxial (−), may appear anomalously biaxial

| birefringence = δ = 0.000

| pleochroism =

| 2V =

| dispersion =

| streak =

| gravity = 4.295 (measured), 4.31 (calculated)

| density =

| melt =

| fusibility =

| diagnostic =

| solubility =

| diaphaneity = transparent

| other = Readily soluble in warm HCl

|references = [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Corkite Mineralienatlas]Mindat.org http://www.mindat.org/min-1130.htmlWebmineral.com http://webmineral.com/data/Corkite.shtmlEuroMin.net http://euromin.w3sites.net//mineraux/CORKITE.html{{Cite web |url=http://www.handbookofmineralogy.com/pdfs/corkite.pdf |title=Handbook of Mineralogy |access-date=2010-07-30 |archive-date=2011-07-28 |archive-url=https://web.archive.org/web/20110728180705/http://www.handbookofmineralogy.com/pdfs/corkite.pdf |url-status=dead }}

}}

Corkite is a phosphate mineral in the beudantite subgroup of the alunite group. Corkite is the phosphate analogue of beudantite and with it, a complete solid solution range exists. Corkite will also form a solid solution with kintoreite.

Corkite is named after County Cork, Ireland; the location where the first notable amount was discovered in 1869. Like many of the other minerals in the beudantite group, corkite is a relatively uncommon, secondary mineral that occurs in oxidation zones near hydrothermal base metal deposits. It occurs associated with pyromorphite, malachite, plumbojarosite, limonite and quartz.