Thursday Challenge — "hard"

I recently visited the Museum of Natural History,
where I found this hard thing:  It's the Star of India,
a 563-carat star sapphire that was donated to
the museum in 1901 by J. P. Morgan.  It was stolen
 in 1964 (at which time it was uninsured and "protected" by
an alarm with a dead battery!).  The thief was caught, the gem
recovered (from a locker in a Miami bus station), and
I assume they've taken better care of this treasure since then.
[To see more of this challenge, go here.]