Have you noticed how some stems seem to have extra sparkle and an extra note to their design? That might be an optic. Glass companies used molded shapes on the interior to give a bit of extra dimension and looks.
Some optics are vertical.
Fostoria Line 5093 Amber Optic Cocktail
Some are subtle. Your eye notices the difference but it doesn’t grab your attention. This Rose Point goblet has a vertical optic.
Rose Point 3500 Water Goblet Vintage Cambridge Stemware
Glass makers must have had fun pushing the envelope. This Fostoria Cabot crystal sherbet has an unusual optic, like dots.
Fostoria Glass Cabot Dot Optic Crystal Sherbet
And this Cellini tumbler, also from Fostoria, has a drape optic.
Fostoria Cellini Sherbet with Drape Optic
And this vase has a loop optic. It’s a beautiful piece and the optic is the entire design.
Loop Optic Green Depression Glass Vase
Some patterns, like the green vase, have the optic as their entire motif. We’ll cover a few next post.