Kokomo Opalescent Glass KOG was founded in 1888 and is the oldest manufacturer of hand-cast, cathedral and opal glass in the USA. KOG is known worldwide for high quality, hand-mixed coloured flat glass. KOG has hundreds of colour formulations, documented colour combinations and numerous textures and densities. Kokomo not only looks positively to the future but also to a glorious past. Industry giants such as Louis Comfort Tiffany, J&R Lamb and La Farge are among the prominent names that appear in the company's early sales documents.