Formula: Mg5(BO3)O(OH)5.2H2O
Origin of name: for Randall H. Wightman (1915-1969), director of exploration and mining, Riverside Cement Company (California - USA).
Crystal system: Monoclinic
Crystal class: 2/m
Twinning:
Unit cell: a = 13.46, b = 3.102, c = 18.17, β = 91.6°
Colour: Colourless with green tint
Diaphaneity: Transparent to semitransparent
Luster: Vitreous
Habit: crystals prismatic, pseudohexagonal, in radiating clusters
Hardness: 5.5
Specific gravity: 2.60
Cleavage: 2; {010} perfect, {100} fair
Tenacity:
Streak: White
Synonyms/varieties:
Comments:
| Back to Alphabetical list | Colour photos | Optical properties/Thin sections | SEM images | TEM images | vibrational spectra description | IR spectra | Raman spectra | N-IR spectra | F-IR spectra | IES spectra |