Origin
USA
Tanzania, Madagascar, Kenya, Sri Lanka, Burma, Australia
Color
Brown, Red, Black, Brownish
Green, Brown, Colorless, Greenish, Yellow
Streak
Reddish, Brown
White
Specific Gravity
5.05-5.22
3.25-3.45
Fracture
Uneven
Conchoidal, Uneven
Cleavage
None
Good on {110}
Chemical Composition
(Zn,Mn2+ ,Fe2+ )(Fe3+ ,Mn3+ ) 2O 4Anthony et al , Handbook of mineralogy (2001)
Mg 3Al 6(Si,Al,B) 5O 21(OH)Walter Schumann , Gemstones of the world (2001) More from other references
Pleochroism
-
X = colorless to green; Y = colorless
Transparency
Translucent
-
Refractive Index
-9999
1.660-1.685
Crystal System
Isometric Hexoctahedral H-M Symbol (4/m 3 2/m) Space Group: F d3m
Orthorhombic
Birefringence
-9999
0.012-0.017
Clarity
Translucent
TransparentUlrich Henn and Claudio C. Milisenda
Psychology
Creativity
Harmony
Healing
-
Emotional healing
Qualities Associated
Grounding
Self-worth