Water_Ice	1.31
Acrylic_Glass	1.491
Benzene	1.501	
Crown_Glass	1.50
Plate_Glass 1.52
Sodium_Chloride	1.544
Amber	1.55	
Polycabonate	1.60	
Flint_Glass	1.62
Bromine	1.661	
Sapphire	1.778
Cubic_Zirconia	2.18
Diamond	2.417	
Silicon	3.48
Germanium	4.05