Brannerite is grey in plane-polarized reflected light. Under crossed polars, it displays yellowish-brown internal reflections and appears isotropic. If large enough (>0.4 mm), densely-intergrown brannerite aggregates appear purplish-brown in obliquely incident light. 🧪
. . . is ascribed the ideal composition, UTi2O6. Actual compositions in the ore sample, however, vary in a manner which satisfies the general composition, (U,Th)1-xTi2+xO6, where x ranges from 0.08 to 0.55. 🧪 . . . /3