Isotropic and anisotropic minerals

Depending upon the optical properties, the minerals can be divided into two groups: (i) isotropic minerals and (ii) anisotropic minerals.

Isotropic Minerals:

In crystals belonging to the cubic system, the light travels with the same velocity in all directions and therefore each mineral has only one refractive index. Such minerals are called ”isotropic minerals”. Non-crystalline substances, such as opal and glass are also isotropic.

An-isotropic Minerals: 

The anisotropic group includes all crystals except those of the cubic system. In these crystals, the velocity of light and consequently the refractive index varies with the crystallographic direction. Anisotropic minerals generally show double refraction.

Read relevant articles:

1. Introduction to the minerals
2. Physical Properties of minerals
3. Specific Gravity of minerals
4. Chemical Properties of minerals
5. Silicate minerals and their groups/types
6. Minerals of Feldspar group
7. Minerals of Feldspathoid group
8. Minerals of Silica Group
9. Minerals of Pyroxene Group
10. Minerals of Amphibole Group
11. Minerals of Mica Group
12. Minerals of Olivine Group
13. Minerals of Garnet Group
14. Minerals of Chlorite Group
15. Minerals of Clay Group
16. Minerals of Serpentine Group
17. Polymorphs/ Minerals of Al₂SiO₅
18. Calcium Minerlas
19. Aluminium Minerals
20. Iron Minerals
21. Manganese Minerals
22. Copper Minerals
23. Miscellaneous Ores
24. Optical Properties of Minerals
25. Refractive Index of Minerals
26. Isotropic and An-isotropic minerals
27. Double Refraction of light in minerals