If you check out the appraisers tab at the top of the pricescope page you'll see who is recommended in the Manhattan Area.
David Wolf www.JustAppraisers.com
Teresa Beltrani www.gemevaluation.com
Joyce Panitch ph: (51
438-1200
Barry Block www.jewelryjudge.net/block.htm
There's 4 to choose from right there, give them a call and see what their capabilities are and if they can meet yor needs. Report back your findings for us. Also, you may consider David Atlas www.gemappraisers.com in Philadelphia, less than 2 hrs away. He's the guy who has developed the cut grading charts for fancy cuts. Are you looking for someone to appraise fancy cut or color?
The cost can vary between about $75 and maybe $200 depending upon the level of service and size of the diamond to be appraised.