Painite

{{Short description|Borate mineral}}

{{Infobox mineral

| name = Painite

| category = Borate minerals

| boxwidth =

| boxbgcolor =

| image = Painite2.jpg

| caption = Painite from Myanmar, 2 cm long

| formula = CaZrAl₉O₁₅(BO₃)

| IMAsymbol = Pai{{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 = 6.AB.85

| dana = 7.5.2.1

| system = Hexagonal{{cite journal |author1=T Armbruster |author2=N Dobelin |author3=A Peretti |author4=D Gunther |author5=E Reusser |author6=B Grobety |year=2004 |journal=American Mineralogist |volume=89 |pages=610–613 |url=http://www.krist.unibe.ch/pdf/2004/painite.pdf |title=The crystal structure of painite CaZrB(Al9O18) revisited |issue=4 |doi=10.2138/am-2004-0415 |bibcode=2004AmMin..89..610A |s2cid=53848992 |access-date=2012-05-28 |archive-url=https://web.archive.org/web/20160304090550/http://www.krist.unibe.ch/pdf/2004/painite.pdf |archive-date=2016-03-04 |url-status=dead }}

| class = Dipyramidal (6/m)
(same H-M symbol), although earlier reported as hexagonal (6)

| symmetry = P6₃/m

| unit cell = a = 8.72 Å,
c = 8.46 Å; Z = 2

| color = Red, brownish, orange-red

| habit = Elongated crystals, pseudo-orthorhombic{{cite journal|vauthors=Claringbull GF, Hey MH, Payne CJ |year=1957|journal= Mineralogical Magazine |volume=31|pages=420–5|doi=10.1180/minmag.1957.031.236.11|title=Painite, a New Mineral from Mogok, Burma|issue=236 |bibcode=1957MinM...31..420C}}

| twinning =

| cleavage =

| fracture =

| tenacity =

| mohs = 7.5 – 8

| luster = Vitreous

| refractive = n_o = 1.8159, n_e = 1.7875

| opticalprop = Uniaxial (-)

| birefringence =

| pleochroism = Ruby-red parallel to [0001]; pale brownish orange or pale

red-orange at right angles to [0001]

| streak = Red

| gravity = 4.01

| density =

| melt = 2094{{Ambiguous|date=July 2020}}{{citation needed|date=July 2020}}

| fusibility =

| diagnostic =

| solubility = Insoluble in acids

| diaphaneity = Transparent

| references = {{cite book|editor1=Anthony, John W. |editor2=Bideaux, Richard A. |editor3=Bladh, Kenneth W. |editor4=Nichols, Monte C. |title=Handbook of Mineralogy |publisher=Mineralogical Society of America |place=Chantilly, VA, US |url=http://rruff.geo.arizona.edu/doclib/hom/painite.pdf |chapter=Paynite |accessdate=December 5, 2011 |isbn=0962209740 |year=2003 |volume=V (Borates, Carbonates, Sulfates)}}[http://webmineral.com/data/Painite.shtml Painite]. Webmineral. Retrieved on 2012-05-28.[http://www.mindat.org/min-3063.html Painite]. Mindat.org. Retrieved on 2012-05-28. }}

Painite is a very rare borate mineral. It was first found in Myanmar by British mineralogist and gem dealer Arthur C.D. Pain who misidentified it as ruby, until it was discovered as a new gemstone in the 1950s. When it was confirmed as a new mineral species, the mineral was named after him.

The chemical makeup of painite contains calcium, zirconium, boron, aluminium, and oxygen (CaZrAl₉O₁₅(BO₃)). The mineral also contains trace amounts of chromium and vanadium, which are responsible for Painite's typically orange-red to brownish-red color,[http://minerals.gps.caltech.edu/FILES/Visible/painite/Index.html Painite history at Caltech]. Minerals.gps.caltech.edu. Retrieved on 2012-05-28. similar to topaz. The mineral's rarity is due to zirconium and boron rarely interacting with each other in nature. The crystals are naturally hexagonal, but may also be euhedral or orthorhombic. They also may have no crystalline structure, but usually are accompanied by a crystalline structure. Until late 2004, only two had been cut into faceted gemstones.[http://io9.com/5902212/ten-gemstones-that-are-rarer-than-diamond Ten gemstones that are rarer than diamond]. io9.com