Antique Chinese celadon urn, wax stamp on base

I inherited this urn, along with several others pieces of Chinese pottery and artwork, after my father passed away last year. I believe that this particular piece was given to my parents as a gift about 20 years ago, from a friend who imported Asian antiques.   

It has a very simplistic designs: not completely symmetric with a jade-green glaze that is worn in some areas but also conspicuously absent from the bottom inch or so of the base. There is also the remainder of some type of wax seal on the bottom of the vessel - possibly used for export purposes?

I would appreciate any info on this item and would like to get an idea of it's value