I myself bought my girl firend a 20k, Diamond ring. it cost £5,500, which is $11,000. Granted, i had won the equivaland of $540,000 on football(soccer) betting, two weeks previous.

   if you do get a 20K ring, its best to get it wih loads of smaller cuts, rather than one single huge diamond, as i did. one huge diamond, while impressive, can be heavy. loads of smaller cuts of it, look much nicer, and are more convinient, while still remaining rare and expensive.