An armature for an illuminant can comprise: walls formed by an armature composition. The armature composition can comprise an armature polymer, 10 wt % to 20 wt % coated titanium dioxide, and greater than zero to 0.001 wt % carbon black, wherein the weight percentages are based upon a total weight of the armature composition. The armature polymer can comprise polycarbonate. At a thickness of greater than or equal to 3 mm, the armature has a reflection at 700 nm of greater than or equal to 93%. A light fixture can comprise a light source in the armature.