# Katayamalite

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{{Short description|Pearly-white radioactive mineral}}
{{Infobox mineral|boxbgcolor=#aaaaaa|image=Katayamalite.jpg|formula=KLi<sub>3</sub>Ca<sub>7</sub>Ti<sub>2</sub>(SiO<sub>3</sub>)<sub>12</sub>(OH)<sub>2</sub>| IMAsymbol   = Kyl<ref>{{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}}</ref>|strunz=9.CJ.25|system=[Monoclinic](/source/Monoclinic)|dana=61.01.04.02|class=Prismatic <br/>[H-M symbol](/source/H-M_symbol): 2/''m''|symmetry=''B''2/b|unit cell=3,179.12|color=White|habit=Tabular, common twinning|cleavage=Perfect on {001}|mohs=3.5 - 4|luster=Vitreous, pearly|opticalprop=Biaxial (+)|refractive=n<sub>α</sub> = 1.670 <br/>n<sub>β</sub> = 1.671 <br/>n<sub>γ</sub> = 1.677|2V=Measured: 32 <br/>Calculated: 46|dispersion=Strong <br>r > v|fluorescence=brilliant blue-white under SW|streak=White|density=2.91|other=25px [Radioactive](/source/Radioactive)}}'''Katayamalite''' is a [cyclosilicate](/source/cyclosilicate) [mineral](/source/mineral) that was named in honor of mineralogist and professor Nobuo Katayama. It was approved in 1982 by the [International Mineralogical Association](/source/International_Mineralogical_Association), and was first published a year later.<ref name=":1" />

== Relation with baratovite ==
Katayamalite is the hydroxyl analogue of [baratovite](/source/baratovite) and the hydroxyl end member of the series,<ref name=":0">{{Cite web|title=Katayamalite Mineral Data|url=http://webmineral.com/data/Katayamalite.shtml|access-date=2021-08-08|website=webmineral.com}}</ref> but was first described as a fluor-dominant mineral. Some scientists claim it to be rather hydroxyl- than fluor dominant, which would make baratovite [isostructural](/source/isostructural) with it. It would make the two minerals the same species, with baratovite having priority. As the case hadn't been clarified, katayamalite remains an IMA-approved mineral until this day.<ref name=":1">{{Cite web|title=Katayamalite|url=https://www.mindat.org/min-4716.html|access-date=2021-08-08|website=www.mindat.org}}</ref>

== Chemical properties ==
Katayamalite mainly consists of oxygen (43.16%), silicon (24.25%), calcium (20.18%), but otherwise contains titanium (6.89%), potassium (2.81%), lithium (1.50%). It has trace amounts of fluorine (0.68%), sodium (0.41%) and hydrogen (0.11%) in its composition as well. It has a barely detectable radioactivity, 40.21 measured in [Gamma Ray American Petroleum Institute Units](/source/Gamma_Ray_American_Petroleum_Institute_Units). The concentration of it in percentage is 2.49. It was originally described as having a [triclinic](/source/triclinic) symmetry in 1985, but the structure was redetermined to be monoclinic in 2013. It has a radiant blue-white fluorescence, and platy morphology.<ref name=":1" />

== Occurrence ==
The mineral is associated with [sugilite](/source/sugilite), [albite](/source/albite) and [aegirine](/source/aegirine).<ref name=":1" /> Crystals are usually [twinned](/source/crystal_twinning). This mineral can be found in aegirine syenite.<ref name=":0" />

== References ==
{{Reflist}}
Category:Monoclinic minerals
Category:Cyclosilicates

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Adapted from the Wikipedia article [Katayamalite](https://en.wikipedia.org/wiki/Katayamalite) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Katayamalite?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.