Can anybody (Ed ... ?) see anything in the linked photo that might say
something about the break? I left the photo big (2000 x 1200) to keep
details.

It's the shank of an SDS max drill bit. Carbide tipped, so I thought
the shank would be mild. Yet, to me, the break looks like that of hard
steel.

Does the varying color mean anything?

http://home.comcast.net/~bobengelhar...42_resized.jpg

Thanks,
Bob