Stones:
Basic body color:
Optical type:
Opical pleochroism:
Colored tourmaline
Red, greed, blue, yellow
Uniaxial,dichroic
Usually a paler/deeper color contrast and green/brown or green/black
Chrysoberyl,deep yellow or brown
Yellow
Biaxial,dichroic or trichroic
Colorless/pale yellow/yellow
Topaz,deep yellow
Deep yellow
Biaxial,dichroic or trichroic
Yellow/pale yellow/pinkish-yellow
Chrysoberyl-alexandrite
Green in daylight,red in tungsten light
Biaxial,trichroic
Green/purplish-red/yellowish in day light,green/orange/red in tungsten light
Beryl-emerald
Green
Uniaxial,dichroic
Bluish-green/yellowish-green
Corundum-ruby
Red
Uniaxial,dichroic
Red/orange red
Beryl-aquamarine
Blue
Uniaxial,dichroic
Colorless or pale blue/sky blue or deep blue
Corundum-sapphire
Blue
Uniaxial,dichroic
Blue/greenish-blue
Synthetic corundum colored by vanadium
Grayish-blue to bluish-purple in daylight, reddish-purple in tungsten light
Uniaxial,dichroic
Brownish-green or yellowish/purplish
Lolite
Blue
Biaxial,dichroic or trichroic
Violet blue/paler blue/pale yellow or blue/pale yellow to near colorless,or two blues
Quartz-amethyst
Mauve,purple,violet
Uniaxial,dichroic
Purple/reddish-purple
Tanzanite
Blue to violet
Biaxial,dichroic or trichroic
Treated blue stones often show deep blue/violet,untreated,trichroic blue/greenish-yellow or yelloe-brown/violet
Zircon,deep blue
Blue
Uniaxial,dichroic
Colorless/sky blue