Amethyst Physical Properties

Amethyst Physical Properties loose sale price & Amethyst Gemstone Information

Amethyst Chemical composition: SiO2 (minor Fe4+ impurities cause amethyst's color)
Class: tectosilicate
Crystal system: Hexagonal-R; 32 (trigonal-trapezohedral)
Crystal habit: Macroscopic crystals occur as horizontally striated hexagonal prisms terminated by a combination of positive and negative rhombohedrons forming six sided pyramids. Amethyst often occurs as drusy masses showing only the rhobohedral terminations. It can also be massive.
Twinning: Dauphine twin with c the twin axis, Brazil twin with {1120} the twin plane
Specific gravity: 2.65
Index of refraction: 1.54-1.55
Birefringence: 0.009
Pleochroism: distinct
Hardness: 7
Color: light to dark purple
Luster: vitreous
Transparency: transparent to translucent
Cleavage: none
Fracture: conchoidal
Streak: white