If you have taken a look at my photo albums and discovered I dropped the button box you will know I am a bit keen on buttons. I have been poking around the sites relate to buttons and button collecting and have a few which people may find interesting. The First is a Button dictionary which is illustrated. The Button Information Index is also useful if you a trying to identify a button. In fact it is eye candy for anyone who likes buttons.
This link relates to the materials that buttons have been made of as it is a link to an article on Bakelite . Written by Lloyd Fadem and Stephen Z. Fadem, M.D. the article covers the invention and history of this early plastic.
Another material that buttons are made of is of course mother of pearl.
Finally Button Images provides information on button collecting including an article on cleaning buttons and how to identify buttons.