Hemihedrite

{{Short description|Rare lead zinc chromate silicate mineral}}

{{infobox mineral

| name = Hemihedrite

| image = Hemihedrite-phoenicochroite-537207.jpg

| imagesize = 260px

| alt =

| caption = Red phoenicochroite and orange hemihedrite microcrystals richly cover the matrix

| category = Chromate mineral

| formula = Pb₁₀Zn(CrO₄)₆(SiO₄)₂(F,OH)₂

| IMAsymbol = Hhe{{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.15

| dana =

| system = Triclinic

| symmetry = P{{overline|1}} (No. 2)

| unit cell = a = 9.49, b = 11.44
c = 10.84 [Å]; α = 120.5°
β = 92.1°, γ = 55.83°; Z = 1

| color = Bright orange, henna-brown, to almost black

| colour =

| habit = Euhedral crystals with hemihedral morphology

| twinning = Present

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| mohs = 3

| luster = Vitreous

| streak = Saffron-yellow

| diaphaneity = Translucent to transparent

| gravity = 6.42

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| opticalprop = Biaxial (+)

| refractive = n_α = 2.105 n_β = 2.320 n_γ = 2.650

| birefringence = δ = 0.545

| pleochroism = Feeble, yellow to orange

| 2V = 88° (measured)

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| references = [http://rruff.info/doclib/hom/hemihedrite.pdf Handbook of Mineralogy][http://www.mindat.org/min-1859.html Hemihedrite on Mindat.org][http://www.webmineral.com/data/Hemihedrite.shtml Hemihedrite data on Webmineral][https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Hemihedrite Mineralienatlas]{{cite journal |last1=McLean |first1=W.J. |last2=Anthony |first2=J.W. |journal=American Mineralogist |volume=55 |year=1970 |pages=1103–1114 |title=The crystal structure of hemihedrite}}

}}

Hemihedrite is a rare lead zinc chromate silicate mineral with formula Pb₁₀Zn(CrO₄)₆(SiO₄)₂(F,OH)₂. It forms a series with the copper analogue iranite.