Looking for info on antique diamond ring….?

I have come across a beautiful ring that is dated to the 1800′s. It is the original platinum setting and the original diamond, it has never been altered. The diamond is around 1.3 carats and is European cut (that indicates it was cut before 1908) and has diamond detail going down the band. It is very intricate and definitely hand made. The number ’23′ is hand carved on the interior band- I’m told this is the signature of the original jeweler. Does anyone have any information on this jeweler or, more importantly, a reasonable market price for an item like this??

I don’t know, but this site may be able to help

http://www.pricescope.com/idealbb/view.asp?topicID=14645

Cut Antique Diamond
Cut Antique Diamond
Cut Antique Diamond