Hogarthite
Hogarthite is an IMA-recognized mineral species in the silicate class, with the chemical formula (Na,K)₂CaTi₂Si₁₀O₂₆·8H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Lemoynite structural group.
Key properties: Mohs hardness 4; specific gravity 2.4; White streak; Satiny to silky to sub-vitreous luster; optically biaxial.
IMA symbol Hog, IMA status: approved, named in 2009.
Found in metasomatically altered marble xenoliths in a breccia zone in association with an alkaline intrusive complex.
It is found associated with Calcite, quartz, haineaultite, labuntsovite-Mn, lemoynite, chabazite, gmelinite-Na.
The mineral was named to honor Donald D. Hogarth (b. 1929), Professor Emeritus, Department of Earth Sciences, University of Ottawa.