Deep blue Maxixe-type color center in beryl

A deep-blue color center can be introduced into some beryl by gamma ray, x-ray, or neutron irradiation. If the original color is yellow or green, then a green or blue-green color can result from introduction of the same color center. This color center is characterized by: (1) strong dichroism with the intense optical absorption in the ordinary ray; (2) narrow band absorptions in the 5000 to 7000 A region in the ordinary ray only; and (3) fading of this center on exposure to light or on heating to above 1000C. Very similar material, showing an absorption spectrum differing only in minor details, was found in Brazil at the Maxixe Mine about 1917, and the modern material has been named ''Maxixe-type'' beryl