Chemistry: Magnesium aluminum iron boro-silicate.
Crystal system: Orthorhombic; radiating columnar habit; water-worn pebbles.
Color: Transparent to translucent; yellow green, brown, colorless; some chrome-rich green; phenomena: chatoyant (golden eye) and asterated stones.
Hardness: 6.5
Cleavage: Prismatic; Fracture: conchoidal.
Specific gravity: 3.3
Refractive index: 1.67 – 1.68; Biaxial negative; 0.013
Luster: Vitreous.
Dispersion: Low
Dichroism: Brown/green.
Occurrence: Star: Burma; Cat’s eye: Sri Lanka; Green: Madagascar, Tanzania, Kenya.
Notes
Collector’s stone; constants near Enstatite; strong spectral band in the violet and a weak band in the blue 503nm; faceted and cabochon.
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