Gems & Gemology, Spring 2013, Vol. 49, No. 1
Strain-Induced Birefringence in Natural Diamond: A Review
D. Howell [email@example.com], European Journal of Mineralogy, Vol. 24, No. 4, 2012, pp. 575–585, http://dx.doi.org/10.1127/0935-1221/2012/0024-2205.
Diamond belongs to the cubic crystal system and should therefore exhibit isotropic optical properties. But it is well documented that diamonds often show weak birefringence. This study has focused on the causes of strain-induced birefringence in natural diamonds: dislocations, lattice parameter variations, inclusions, fractures, and plastic deformation.
Strain patterns shed light on the internal stresses within the stone, which in turn reveal the growth and transport history of the diamond. The imaging of diamonds between crossed polarizers remains a simple and rapid technique for obtaining visual information on strain patterns in diamonds.
Abstracted by Guy Lalous