NID: Clear etched glass tumblers
Hello. Any idea as to what time period these clear glass tumblers were made? What is the small circle on the center bottom? Are these mold blown? They have a 4 ring cuts and a daisy etching on two opposite sides on a flared body measuring 2 1/2" at the top and 2 1/8" at the base. There are 14 vertical optic flutes with a pressed slightly inverted mold blown bottom? Measure about 3 7/8" tall x 2 1/2" opening. The glass in incredible clear. Any help is greatly appreciated.