Ivory has been used on guitars for a long time and in fact Martin (big, old,
good guitar maker Jeff) used some real ivory until the 1980’s.  When it is thin
like a piano key, I have seen red paint in the recess before the ivory and it
gives it a nice color.

I just copied a Martin from pre-civil war times and put a faux ivory bridge on
it - the original would have been covered in ivory stuff.  It is redwood and
maple where the originals would have been spruce and maple.  All of the other
white-ish strips are what is called Ivoroid.  This is a very early plastic made
from the residue of photography chemicals - the oldest plastic was this stuff in
1858 (??)Many piano keys were made of this starting in the 1870’s.

I love this instrument  - Click left and right, text below, and my daughter
plays a little tune on the last frame:


https://www.flickr.com/photos/ruby1638/50356331877/in/album-72157678301955987/


Ed Minch