Does diamond exhibit birefringence? If not, why?

• A. Yes
• B. No; because diamond is a cubic crystal and is singly refractive
• C. Only under polarized light
• D. It does under certain colors

Answer: (B)

Birefringence happens when a material is optically anisotropic, causing light to travel with two different refractive indices along different directions and split into two rays. Diamond belongs to the cubic (isometric) crystal system, which is highly symmetric. In cubic crystals, the refractive index is the same in all directions, so light doesn’t split and the material is optically isotropic. That’s why diamond is singly refractive and does not exhibit birefringence under normal conditions. If you ever see birefringence, it’s usually due to stress or defects causing localized, stress-induced birefringence rather than an intrinsic property of a perfect diamond.