Some representative refractive indices
Material λ (nm) n Ref.
Vacuum 1 (by definition)
Air at STP 1.000277
Gases at 0 °C and 1 atm
Air 589.29 1.000293 [1]
Carbon dioxide 589.29 1.00045 [2]

[3] [4]

Helium 589.29 1.000036 [1]
Hydrogen 589.29 1.000132 [1]
Liquids at 20 °C
Arsenic trisulfide and sulfur in methylene iodide 1.9 [5]
Benzene 589.29 1.501 [1]
Carbon disulfide 589.29 1.628 [1]
Carbon tetrachloride 589.29 1.461 [1]
Ethyl alcohol (ethanol) 589.29 1.361 [1]
Silicone oil 1.336-1.582 [6]
Water 589.29 1.3330 [1]
10% Glucose solution in water 589.29 1.3477 [7]
20% Glucose solution in water 589.29 1.3635 [7]
60% Glucose solution in water 589.29 1.4394 [7]
Solids at room temperature
Titanium dioxide (Rutile phase ) 589.29 2.496 [8]
Diamond 589.29 2.419 [1]
Strontium titanate 589.29 2.41
Amber 589.29 1.55 [1]
Fused silica (also called Fused Quartz) 589.29 1.458 [1]
Sodium chloride 589.29 1.544 [9]
Other materials
Liquid helium 1.025
Water ice 1.31
Cornea (human) 1.373/1.380/1.401 [10]
Lens (human) 1.386 - 1.406
Acetone 1.36
Ethanol 1.36
Glycerol 1.4729
Bromine 1.661
Teflon AF 1.315 [11]
Teflon 1.35 - 1.38
Cytop 1.34 [12]
Sylgard 184 (Polydimethylsiloxane) 1.4118 [13]
PLA 1.46 [14]
Acrylic glass 1.490 - 1.492
Polycarbonate 1.584 - 1.586
PMMA 1.4893 - 1.4899
PETg 1.57
PET 1.5750
Crown glass (pure) 1.50 - 1.54
Flint glass (pure) 1.60 - 1.62
Crown glass (impure) 1.485 - 1.755
Flint glass (impure) 1.523 - 1.925
Pyrex (a borosilicate glass) 1.470 [15]
Cryolite 1.338
Rock salt 1.516
Sapphire 1.762–1.778
Sugar Solution, 25% 1.3723 [16]
Sugar Solution, 50% 1.4200 [16]
Sugar Solution, 75% 1.4774 [16]
Cubic zirconia 2.15 - 2.18
Potassium Niobate (KNbO3) 2.28
Silicon carbide 2.65 - 2.69
Cinnabar (Mercury sulfide) 3.02
Gallium(III) phosphide 3.5
Gallium(III) arsenide 3.927
Zinc Oxide 390 2.4
Germanium 4.01
Silicon 590 3.962 [17]