1.19 ct. Londonite

Londonite is the cesium rich end-member of the Rhodizite-Londonite series.  And while both species are rare as gems, Londonite is by far the rarest of the two - it is found in only in a very limited series of pegmatites in Madagascar.  The particular deposit that produced this gem has been analyzed and found to be some of the purest Londonite ever found.  The gem is an attractive light yellow and exceedingly well cut - at 8 on the Moh's scale Londonite is very hard for a gem in the 'rare stone' category, so it can take a high polish.  Lovely example. 

$700 / carat - $833 total