Andelucite, named after Andalussia in Spain, has geological intreste due to it's strong pleochoism. Large piceses of gem quality stone are rare. It has a vitreous luster. It occurs in shists, genisses, and in river gravel. Cuttable qualities come from Brazil and Sri Lanka. Also from Canada (Quebec), Spain (Almeria/Andalusia), Russia and the U.S. (Main, Massachusetts). It can be confused with chrysoberyl, spokey quartz, and tourmaline.

• Color : Yellow, green, brown-red
• Color or streak : White
• Mohs' hardness : 7 1/2
• Specific gravity : 3.12 - 3.18
• Cleavage : Imperfect
• Fracture : Uneven, brittle
• Crystal system : Orthorhombic; thick
  lon crystals, elongated and grainy
  aggregates
• Chem. Composition : Al(AlSiO5)
  aluminium silicate
• Transparency : Transparent
• Refractive index : 1.641 - 1.648
• Double refraction : -0.007
• Dispersion : 0.016
• Pleochroism : Strong; yellow, olive,
  red-brown to dark-red
• Absorption spectrum : 5535, 5505,
  5475, (5250), (5180), (5060),
  (4950), 4550, 4475, 4360
• Flourescence : Weak; green, yellow-
  green