Set Four vintage Fiesta Amberstone 10" Dinner Plates was sold in the 1960's as the Sheffield Line, made by Homer Laughlin. They was distributed to major grocery store chains for promotions.

I purchased these Dinner Plates at an estate, along with other Vintage Fiesta pieces and was amazed to find they were in such great condition,( never been used) and still has that new shinny gloss of new! Some I had to remove the stuck on plastic from them that they came packed in. 
Any spots you might see in the photos are from camera flash glares from the camera and not flaws.

If you collect vintage Fiesta pieces I know you would be delighted to have this Fiesta Amberstone Dinner Plate added to your collection and, it doesn't get any better than "Never Been Used!" in vintage Fiesta