Use these stainless steel earring cabochon settings to set a cabochon with glue, such as E6000, or make other creations within the cup with resin, polymer clay or whatever else you may imagine.
They measure 10.5mm with a cup depth of 1mm. The ear pin is 0.5mm thick.
E6000 can be found at most retail craft stores and hardware stores.
Gold elephants earrings using these trays courtesy of Annica of Etsy shop HappyElephantArt.