My friend recently went to Ecuador and visited a button factory. "I had a tour today and it was quite informative. I learned of a new kind of coconut seed know as the Tagua. It is about the size of an avocado. When it is first harvested it is edible and some of the nuts are used for nutritional purposes. Most, however, are left in the sun to harden and turn into what is knows as vegetable ivory. This ivory has many decorative purposes but the main use seems to be to make buttons. The shells are sliced, then have a hole drilled through them and the round piece of ivory is used to make buttons. All of the waste material is ground up and used for cattle feed. It was quite fascinating to see the whole process from nut to finished product."
These are some of the buttons he brought back, for sale under Misc. materials at Pegs Buttons