The Wedgewood company started in Burslem, England in 1759.  The term "Jasperware" is pattened by the company, and is actually a type of stoneware.  It has a matte finish, and comes in a few different colors such as blue, green, yellow, lilac and black.  The blue is the most famous and has become known as "Wedgewood Blue".
 
This ashtray is marked with "1954" and is 4" across.  Some staining as shown.