WRITTEN BY RIYA DUBEY
Uchiha Obito is a former student of Minato Namikaze and a former teammate of Rin and Kakashi Hatake. Obito and Kakashi used to have a rivalry before Obito got crushed by a rock trying to save Kakashi.
After being crushed, he gave his one Sharingan to Kakashi as a present. However, Obito did not die, he was saved by Madara and then was fed false information and manipulated and turned evil.
Throughout all the identity changes Obito went through, he always donned a mask. His mask's appearance kept on changing.
It was orange when he was pretending to be Tobi. It was white with both of his eyes visible during the Shinobi war as he wanted the world to see his Rinnegan.
The specialty of his mask is that Byakugan cannot see through it. Even though Byakugan can see a person's chakra point and much more, it was unable to see through Obito's mask.
In 'Boruto', Sasuke used some mineral dust to obstruct clairvoyant powers. Obito's mask may have the same mineral which prevents clairvoyant powers such as the Byakugan from seeing through it.
As for the base material, there has never been any confirmation regarding Uchiha Obito's mask, but fans theorize that it is made of a special kind of clay.
They theorize that as in 'Naruto' when his mask broke, a sound similar to clay breaking was heard. This is all that is known about the nature of Uchiha Obito's mask.