Emerald (Flux Growth) Classification
Emerald (Flux Growth)
Light To Very Dark Green To Strongly Bluish Green, Slightly Yellowish Green
Refractive index, birefringence, optic character distinguished beryl from other materials, but magnification is essential for separating synthetic beryl from natural material.
Misnomer: cultured emeraldChatham material: RI 1.561 to 1.564, Fluorescence: stones will show a weak to moderate red in LW and SW but stronger reaction LW.Gilson I material RI: 1.564 to 1.569, SG: 2.66; Gilson II material RI: 1.562 to 1.567, SG: 2.66Gilson I & II material: Fluorescence: generally stones show a weak to moderate red reaction under LW and SW, but with a stronger reaction to LW; other stones might have weak to moderate yellowish green, yellow or orange reaction under LW and SW.Gilson III material RI:1.57 to 1.579, Fluorescence: Inert, SG 2.68 to 2.69.Russian material RI: 1.559 to 1.563 Fluorescence: stone will show a weak to moderate orange-red reaction under LW and they are inert to SW, SG: 2.66