katayamalite

{{Infobox mineral|boxbgcolor=#aaaaaa|image=Katayamalite.jpg|formula=KLi3Ca7Ti2(SiO3)12(OH)2| IMAsymbol = Kyl|strunz=9.CJ.25|system=Monoclinic|dana=61.01.04.02|class=Prismatic H-M symbol: 2/m|symmetry=B2/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=nα = 1.670 nβ = 1.671 nγ = 1.677|2V=Measured: 32 Calculated: 46|dispersion=Strong r > v|fluorescence=brilliant blue-white under SW|streak=White|density=2.91|other=25px Radioactive}}Katayamalite is a cyclosilicate mineral that was named in honor of mineralogist and professor Nobuo Katayama. It was approved in 1982 by the International Mineralogical Association, and was first published a year later.

== Relation with baratovite == Katayamalite is the hydroxyl analogue of baratovite and the hydroxyl end member of the series, 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 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.