Phone makers have converged on one design for premium models - a metal frame sandwiched between two panes of glass. It's a practical choice, the metal gives rigidity to the thin, long phones while glass lets radio waves and wireless charging through. The number of phones that incorporate metal in their build has been rising in recent years. While some phones use plastic for the back instead of glass, the chart below shows that glass is by far the most typical choice. It's interesting to see companies experiment with ceramics instead of glass. Some ceramics are transparent to radio...
Source: https://www.gsmarena.com/counterclockwise_the_rise_of_the_metal_phone-news-30645.php
