This cobalt tumbler is decorated with silver nitrate in a wave pattern and then iridized to make this sparkling, deep, creamy rainbow effect. A vaguely Lalique-esque decoration that's a bit like mermaids in an ocean storm.
NOTE: The nature of handblown glass is that every piece is truly unique. At Sirius we don't strive for factory line perfection and opt to embrace the fluid nature of molten glass allowing for some organic shaping and patterning of the glass. Your tumbler may not look exactly as pictured here. It will vary slightly in size and patterning. Tumblers are roughly between 5 and 6 inches tall and around 3 inches wide.