Depends on what you are looking for...AND more importantly, who graded it, and how nicely cut it is! My local jewelry store sells 1 carat stones for anywhere from $2,000 to like $10,000, so that gives you a great range...
Personally I wouldn''t do it without a LOT more information like who it was certified by (AGS or GIA are good reliable ones, others don''t matter much). Otherwise, I''d pass personally.