Jasperware was matte finish pottery product (some refer to it as porcelain)developed by Josiah Wedgwood and used to imitate onyx or sardonyx in that it had a background color (usually blue, but not always) with the white design in relief.

Example of the Wedgewood Mark - 1908 to 1969

Date	Jasperware Markings
Prior to 1860	Wedgewood
1860 - 1891	Three Letters: Month, Potter, Year
1891 - 1908	Wedgewood England (stamped separately)
1908 - 1969	Wedgewood Made in England (stamped separately)
1970 - Present	Wedgewood Made in England