Icons are normally considered to be just visual when designing an application and aren't given much priority, whereas they are the first element of your product a user interacts with. Generally Developers and Designers tend to stick a logo with a little shadow to call it an icon, but that's not it.
Iconography is far more complex especially when we talk in terms of it being WRT Material Design. Material design takes inspiration from Ink and Paper to use their physical properties such as cuts, folds and light to emulate icons as paper itself.
We skim through the basic thing to keep in mind while creating icon prototypes with Material Design with an actual physical first of it's kind workshop involving how to cast shadows, tints, shades, Z axis elevation and a lot of Craft and Origami.
This was conducted in SPIT College, Andheri on 22-08-15, courtesy of TechVed Consulting, where participants created beautiful material design icons on paper.