Hi Reza,

Thank you for contacting Mearto with your appraisal inquiry.
In 2008, Heritage Auctions sold a MS64 1817half bust in "near gem" condition for $6,900 (https://coins.ha.com/itm/bust-half-dollars/1817-50c-ms64-ngc/a/454-1473.s); I can't tell from the tarnishing of YOUR example if the grading is correct. My understanding that once a coin is graded, it automatically goes into the census but I can't say where in that census it currently stands.The tarnishing would negatively impact the value a little, which I would put at $4,000-6,000.*

*represents a fair-market value for auction purposes; retail or asking price may vary.

Please let us know if you have additional items to appraise, and thank you again for using Mearto.