Hydrokenoralstonite

Renamed from ralstonite after being moved into the Pyrochlore Supergroup (IMA July 2016; Atencio et al., 2017). The earlier reported "AHF" phase (hydrated aluminum hydroxy-fluoride) and the "ralstonite-like mineral" (Desborough & Rostad, 1980; Keith, 1991; Rosenberg 2006) are also hydrokenoralstonite. Compare fluornatrocoulsellite and UM1941-01-F:AlCaHMgNa.

History

Activities related to discovery and approval of the group members

Structural context

Hydrokenoralstonite
Crystal System isometricCrystal Class hexoctahedralSpace Group Fd-3m
a9.87—9.91 (9.8943)
b9.87—9.91 (9.8943)
c9.87—9.91 (9.8943)
alpha90
beta90
gamma90
volume961.505—973.242 (968.6427)

Based on 3 measurements

Chemical context

Stoichiometric formulas

Hydrokenoralstonite
mindat.org
  • March 13, 2023Na0.5(Al,Mg)2(F,OH)6·H2O
IMA
  • March 13, 2023◻2Al2F6(H2O)
mineralogy.rocks
  • Aug. 30, 2022[box]2Al2F6(H2O)

Elements recorded on EPMA

3
Al
3
F
3
H
3
Mg
3
Na
3
O

Physical properties

ColorColor entities, recognized using a custom trained NER model
  • colourless
    Color noteOriginal color note from the source
    Colourless, white
    StreakStreak entities, recognized using a custom trained NER model
      Streak noteOriginal streak note from the source
      White
      Lustre
      Vitreous
      Fracture
      Irregular/Uneven
      Transparency
      Transparent
      Translucent
      Tenacity
      brittle
      Hardness
      5
      Measured density
      2.56—2.62