Mineral - Benitoite
Benitoite
Chemical Properties
Mineral Class
Silicates
Toxicity
none
Formula
BaTi(Si₃O₉)
Unit Cell
a=6.64 c=9.76 Z=2
Physical Properties
Hardness
6 - 6.5
Streak
white
Density
Normal (2-3,5)
Cleavage
Indistinct after {10 1 1}
Fracture
conchoidal
Tenacity
Brittle
Optical Properties
Color
whiteblue
Birefringence
0.046
Luster
Vitreous,
Adamantine
Transparency
translucent,
transparent
Pleochroism
X: Farblos-Blau
Y: Blau-Violett
Geomineralogical Properties
Crystal System
hexagonal
Point Group
ditrigonal-dipyramidal - 6 m2
Space Group
P 6 2c (190)
Habit
prismatic, pyramidal
Formation
Through metasomatism in serpentinites
Paragenesis
Twinning
Rarity
Rarely
Synonyms
Benitoite
Composition
Elements
Mass
SiO₂
42.62
TiO₂
19.44
BaO
37.27
Na₂O
0.14
California (Louderback 1909)
Groups and Members
Benitoite-Group
Name and first discovery: Named after the type locality in San Benito County, California, USA. First described in 1907.
Chemism:
Synonyms:
Varieties:
Abbreviation: Bni
Literature
Louderback, G. D. (1909). Benitoite, its paragenesis and mode of occurrence. Universityof California Publications, Bulletin of the Department of Geology, 5, 331-380.