Yarzhemskiite
Yarzhemskiite is an IMA-recognized mineral species in the borate class, with the chemical formula K[B₅O₇(OH)₂]·H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Larderellite structural group.
Key properties: Mohs hardness 2.5; specific gravity 2.13; White streak; Vitreous luster; optically biaxial.
IMA symbol Yzm, IMA status: approved, named in 2018.
Found in a halite-sylvite evaporitic rock in a salt dome. Formed by diagenesis or post- diagenetic processes.
It is found associated with Carnallite, polyhalite, gypsum, strontioginorite, satimolite, quartz. Distribution From the Chelkar salt dome (drillcore of borehole #800, depth 344-347 m).
The mineral was named to honor Russian geologist, petrologist, and mineralogist Yakov Yakovlevich Yarzhemskii (1901-?).