Paralaurionite

{{Short description|Colorless mineral}}

{{infobox mineral

| name = Paralaurionite

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| image = Paralaurionite.jpg

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| caption = Platey clear paralaurionite crystals from slag in the Thorikos area, Lavrion, Attica, Greece

| category = Halide mineral

| formula = PbCl(OH)

| IMAsymbol = Plri{{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 = 3.DC.05

| dana =

| system = Monoclinic

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

| symmetry = C2/m

| unit cell = a = 10.865(4) Å,
b = 4.006(2) Å,
c = 7.233(3) Å;
β = 117.24(4)°; Z = 4

| color = Colorless, white, pale greenish, yellowish, yellow-orange, rarely violet

| colour =

| habit = Elongated tabular crystals

| twinning = Contact twinning on {100}

| cleavage = Perfect on {001}

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| tenacity = Flexible, non-elastic

| mohs = 3

| luster = Subadamantine

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| diaphaneity = Transparent to translucent

| gravity = 6.05–6.15

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| opticalprop = Biaxial (−)

| refractive = n_α = 2.050 n_β = 2.150 n_γ = 2.200

| birefringence = δ = 0.150

| pleochroism = Visible

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| references = [https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Paralaurionite Mineralienatlas][http://rruff.geo.arizona.edu/doclib/hom/paralaurionite.pdf Handbook of Mineralogy][http://www.mindat.org/min-3096.html Paralaurionite on Mindat.org][http://www.webmineral.com/data/Paralaurionite.shtml Paralaurionite on Webmineral]

}}

Paralaurionite is a colorless mineral consisting of a basic lead chloride PbCl(OH) that is dimorphous with laurionite. It is a member of the matlockite group.{{cite book|title=Mineralogical magazine|url=https://books.google.com/books?id=KGfzAAAAMAAJ|accessdate=26 January 2012|date=1 January 2006|publisher=Mineralogical Society, HighWire Press|pages=643–8}} The name is derived from para-, the Greek for "near", and laurionite, because of its polymorphic relationship to it. Bright, yellow tips of thorikosite can form on paralaurionite crystals and paralaurionite may also be intergrown with mendipite.{{cite book|title=The Mineralogical record|url=https://books.google.com/books?id=nT0eAQAAMAAJ|accessdate=26 January 2012|year=1986|pages=185–88}}{{cite book|last=Williams|first=Peter A.|title=Oxide zone geochemistry|url=https://books.google.com/books?id=T1cSAQAAIAAJ|accessdate=26 January 2012|date=August 1990|publisher=E. Horwood|isbn=978-0-13-647553-8|pages=262–4}}