A list of refraction indices for a number
of common materials that you can plug into Snell's Law:
Vaccuum 1.000000
Helium 1.000036
Hydrogen 1.000140
Oxygen 1.000276
Argon 1.000281
Air 1.0002926
Nitrogen 1.000297
Carbon Dioxide 1.000449
Liquid Hydrogen 1.0974
Liquid Nitrogen 1.2053
Water at 00C 1.309
Water at 1000C 1.31819
Alcohol 1.329
Water 350C 1.33157
Acetone 1.36
Ethyl Alcohol 1.36
Chlorine 1.385
Fluorite 1.434
Opal 1.450
Quartz 1.45843
Carbon Tetrachloride 1.460
Plastic 1.460
Turpentine 1.472
Glycerine 1.473
Plexiglass 1.50
Benzene 1.501
Glass 1.51714
Ruby 1.760
Sapphire 1.760
Sulphur 1.960
Crystal 2.00
Diamond 2.417
Steel 2.50
Silicon 4.24