Your find came from a Hepplewhite furniture piece. It's either a hardware knob or a rosette that would be found on a mirror. The urn is so typical of that period. The Hepplewhite period started around 1810, so your furniture rosette is an old one! The 'urns' decor was also used during the Queen Anne period, but is most associated with Hepplewhite. Here's a website showing the Hepplewhite urn on hardware.
http://www.treasurenet.com/forums/my-best-finds/327751-what-your-single-finest-find-2012-a-new-post.html
<img src="http://www.treasurenet.com/forums/attachment.php?attachmentid=736985"/>
Neat find

Breezie