Formula: NaxMgxAl2-x(F,OH)6.H2O
Origin of name: for J. Grier Ralston, of Norristown, Pennsylvania, USA
Crystal system: cubic
Crystal class: 4/m -3 2/m
Twinning:
Unit cell:
Colour: colourless, white
Diaphaneity: transparent to translucent
Luster:
Habit: crystals octahedral, cubo-octahedral or cubic
Hardness: 4.5
Specific gravity: 2.56 to 2.62
Cleavage: 1; {111} imperfect
Tenacity:
Streak:
Synonyms/varieties:
Comments: structurally related to pyrochlore
| Back to Alphabetical list | Colour photos | Thin sections | SEM images | TEM images | vibrational spectra description | IR spectra | Raman spectra | N-IR spectra | F-IR spectra | IES spectra |