| The following table shows the refractive index (value for air at the same temperature) of various substances for light of various wavelengths, and is shown in the lower column. ⊿ is the temperature coefficient of refractive index for the sodium D line (wavelength 589.3 nm). | |||||||||
| wavelength λ/nm |
Calcite 18℃ | Crystal 18℃ | quartz Glass 18℃ |
Fluorite CaF2 18℃ |
rock salt 18℃ |
Sylvin KCI 18℃ |
water 20℃ |
||
|---|---|---|---|---|---|---|---|---|---|
| Normal ray | Abnormal rays | Normal ray | Abnormal rays | ||||||
| 9429.0 | － | － | － | － | － | 1.3161 | 1.4983 | 1.4587 | － |
| 4200.0 | － | － | 1.4569 | － | － | 4078 | 5213 | 4720 | － |
| 2172.0 | 1.6210 | 1.4746 | 5180 | 1.5261 | － | 4230 | 5262 | 4750 | － |
| 1256.0 | 6388 | 4782 | 5316 | 5402 | － | 4275 | 5297 | 4778 | 1.3210 |
| 656.3 | 1.6544 | 1.4846 | 1.5419 | 1.5509 | 1.4564 | 1.4325 | 1.5407 | 1.4872 | 1.3311 |
| 589.3 | 6584 | 4864 | 5443 | 5534 | 4585 | 4339 | 5443 | 4904 | 3330 |
| 546.1 | 6616 | 4879 | 5462 | 5553 | 4602 | 4350 | 5475 | 4931 | 3345 |
| 404.7 | 6813 | 4969 | 5572 | 5667 | 4697 | 4415 | 5665 | 5097 | 3428 |
| 303.4 | 1.7196 | 1.5136 | 1.5770 | 1.5872 | 1.4869 | 1.4534 | 1.6085 | 1.5440 | 1.3581 |
| 214.4 | 8459 | 5600 | 6305 | 6427 | 5339 | 4846 | 7322 | 6618 | 4032 |
| 185.2 | － | － | 6759 | 6901 | 5743 | 5099 | 8933 | 8270 | － |
| ⊿ | +5x10-6 | +14x10-6 | -5x10-6 | -6x10-6 | -3x10-6 | -1x10-5 | -4x10-5 | -4x10-5 | -8x10-5 |
| References: "Chronological Scientific Tables" (National Astronomical Observatory, 2000 edition) Physical / Chemical Optical Properties 97 (521) Quoted from the refractive index of various substances. | |||||||||