It turns out that the colorful interchangeable shells that the Nokia Lumia 625 will be available with have been given additional thought compared to the first polycarb iterations of Nokia. They are translucent, like on the Lumia 620, and the paint is layered from the inside for a "warm glow" look, while the matte finish adds to a more human feel in the hand. Pretty good results, we'd say, showing that Nokia isn't resting on its laurels when it comes to the use of deep-colored polycarb in its signature pillowy Lumias...
Source: http://www.phonearena.com/news/Nokia-Lumia-625-comes-with-a-new-generation-of-polycarbonate-shells_id45605
Source: http://www.phonearena.com/news/Nokia-Lumia-625-comes-with-a-new-generation-of-polycarbonate-shells_id45605