I found this Stanley #39 folding rule last week.

Made of Ivory

sadly one part was broken years ago

nov144 by Skip Albright, on Flickr

nov146 by Skip Albright, on Flickr

Out of all of them I own, I don't have any ivory ones.  Probably my luck if I ever find 1 in the wild that it would be broken too.  No matter- it's still a great find.

Neat find. 

I wonder what the benefit of ivory was?  Not, obviously, strength (note, though, that I've seen plenty of broken boxwood rules).  Stability?  Ease of reading?  Or just bragging rights?

I have always assumed stability and a bit of bragging rights, but there may be a good reason.