Brooch.

Vitreous enamel, copper, oxidized sterling silver, 24k gold, mirror

Note: These are tiny bits of enamel applied in numerous layers undergoing multiple firings to build up the unique glass texture. Light is subtly reflected from inner gold surface.

Contemporary art jewelry brooch of vitreous enamel by Wendy McAllister.
"BUBBLING"
Brooch.
Vitreous enamel, copper, oxidized sterling silver, 24k gold, mirror