The physical properties of sodium chloride (e.g. structure, density) determine how it is produced and used. Cubic sodium chloride crystals are formed as seawater or saline lake water evaporates or in underground salt formations. Physical properties of pure sodium chloride include:
| Crystal form | isometric, cubic |
| Crystal system | orthorhombic |
| Cleavage | perfect, all sides - cubic |
| Fracture | conchoidal |
| Color | clear to white |
| Index of refraction | 1.5442 |
| Density or specific gravity | 2.165 (135 lb/ft3) |
| Bulk density, approximate (dry, ASTM D 632 gradation) | 1.154 (72 lb/ft3) |
| Angle of repose (dry, ASTM D 632 gradation) | 32° |
| Melting point | 800.8° C (1,473.4° F) |
| Boiling point | 1,465°C (2,669° F) |
| Hardness (Moh’s Scale) | 2.5 |
| Critical humidity at 20 °C, (68° F) | 75.3% |
Density of sodium chloride
| Per Cent by Weight in Solution | Density of Sodium Chloride Solutions | |||||||||
| 0°C | 10°C | 20°C | 25°C | 30°C | 40°C | 50°C | 60°C | 80°C | 100°C | |
| 1 | 1.00747 | 1.00707 | 1.00534 | 1.00409 | 1.00261 | 0.99908 | 0.99482 | 0.99000 | 0.97850 | 0.96510 |
| 2 | 1.01509 | 1.01442 | 1.01246 | 1.01112 | 1.00957 | 1.00593 | 1.00161 | 0.99670 | 0.98520 | 0.97190 |
| 4 | 1.03038 | 1.02920 | 1.02680 | 1.02530 | 1.02361 | 1.01977 | 1.01531 | 1.01030 | 0.99880 | 0.98550 |
| 6 | 1.04575 | 1.04408 | 1.04127 | 1.03963 | 1.03781 | 1.03378 | 1.02919 | 1.02410 | 1.01250 | 0.99940 |
| 8 | 1.06121 | 1.05907 | 1.05589 | 1.05412 | 1.05219 | 1.04798 | 1.04326 | 1.03810 | 1.02640 | 1.01340 |
| 10 | 1.07677 | 1.07419 | 1.07068 | 1.06879 | 1.06676 | 1.06238 | 1.05753 | 1.05230 | 1.04050 | 1.02760 |
| 12 | 1.09244 | 1.08946 | 1.08566 | 1.08365 | 1.08153 | 1.07699 | 1.07202 | 1.06670 | 1.05490 | 1.04200 |
| 14 | 1.10824 | 1.10491 | 1.10085 | 1.09872 | 1.09651 | 1.09182 | 1.08674 | 1.08130 | 1.06940 | 1.05650 |
| 16 | 1.12419 | 1.12056 | 1.11621 | 1.11401 | 1.11171 | 1.10688 | 1.10170 | 1.09620 | 1.08420 | 1.07130 |
| 18 | 1.14031 | 1.13643 | 1.13190 | 1.12954 | 1.12715 | 1.12218 | 1.11691 | 1.11130 | 1.09930 | 1.08640 |
| 20 | 1.15663 | 1.15254 | 1.14779 | 1.14533 | 1.14285 | 1.13774 | 1.13238 | 1.12680 | 1.11460 | 1.10170 |
| 22 | 1.17318 | 1.16891 | 1.16395 | 1.16140 | 1.15883 | 1.15358 | 1.14812 | 1.14250 | 1.13030 | 1.11720 |
| 24 | 1.18999 | 1.18557 | 1.18040 | 1.17776 | 1.17511 | 1.16971 | 1.16414 | 1.15840 | 1.14630 | 1.13310 |
| 26 | 1.20709 | 1.20254 | 1.19717 | 1.19443 | 1.19170 | 1.18614 | 1.18045 | 1.17470 | 1.16260 | 1.14920 |