I think a couple pieces I have picked up recently are lusterware. Trying to find more information online about it, I found these links.
http://www.countryliving.com/antiques/appraisals/lusterware-teacup-0508 from here I learned it comes in different colors then just the gold I have.
I found this defination:
lusterware, kind of pottery with an overglaze finish containing copper and silver or other materials that give the effect of iridescence. The process may have been invented and was certainly first popularized by Islamic potters of the 9th cent. The most beautiful and brilliantly colored ware-pottery that was made between 836 and 883 for the Abbasid caliphs-has been found at Samarra. During the reign (10th-12th cent.) of the Fatimids in Egypt a high standard was maintained. Iranian and Egyptian potters continued to produce lusterware, while in Europe it was manufactured chiefly in Spain and then in Italy, where in the 15th cent. it was sometimes used to enhance majolica. In England the technique came into vogue in the 19th cent. and was utilized by Josiah Wedgwood and Josiah Spode.
and this one:
Pottery or porcelain having a metallic sheen produced when metallic oxides are added to the glaze.
Good definition here on ebay
My pieces are from Japan-and found this article http://www.harryrinker.com/col-949.html
I found a beautiful example here http://www.atticshoppe.com/porcelain/js2095.htm
I don't think the photos do these pieces justice-you can't see the luster or how gorgeous these are
I was glad to learn that the pieces from Japan I have picked up that are lusterware then, are from the 1920s- to the 1930s.