The auction catalogue is the best bet.
Also, you may want to look on
TRHIS THREAD for the sake of the un-named, huge round pearl set in right... err... you'll see what I mean. There really can't be too many candidates for the sheer size and implied natural provenance.
Just to add an IMO bit: I am a bit confused by the name: 'pellegrina' does not mean 'incomparable' in any language, although the name could be explained by the attribution of the 'Pilgrim pearl' name (with more or less precise spelling) to various remarkable jewels before Ms. Taylor acquired the one you want to avoid and thus re-established a unique object to the name. It is not certain that her pear is the same as the historic, the association was a bit of a matter of fate and is now established by tradition again.