tumblers that are guaranteed for life Optimize your serving space with Diamond, the stacking tumblers from Aspen. From Bloody Mary’s and margaritas to beer and shots of tequila, these virtually unbreakable tumblers are made of Polycrystal, a superior food grade drinkware that is sure to impress. In fact, we guarantee its quality by offering a lifetime guarantee against breaks, cracks and shatters under normal use. Looking to customize your beverage experience? Diamond is also available in a handful of great colors to add that extra flair to the tabletop.