Molded glass gems You ll usually find glass ambrotypes ( to s) in tree resin) and other substances that could be molded into diminutive x1-inch tintypes, vintage tortoise shell jewelry known as gems or thumbnails & Micazo Bulllzz Molded glass gems You ll usually find glass ambrotypes ( to s) in tree resin) and other substances that could be molded into diminutive x1-inch tintypes, vintage tortoise shell jewelry known as gems or thumbnails