A bit of a mystery. This has an OWL and 17 U P on pin and Reading Branch. I acquired it from an antique shop almost 30 years ago. The seller indicated it was from the Wharton School of Accounts and Finance 1917 - but I have been unable to determine that or find a Reading Branch (though that could also be an alumni chapter from Reading - which would tie this up with a bow - but it is still a question mark). 

Caldwell 14K Gold stamped. I do see other jewelry from this era produced by a J. E. Caldwell but I have not been able to tie this to that firm yet.

It does appear to be U Penn 1917 at the least.

Thanks!