Beautiful, but a little out of ordinary. Famous for being light weight and for its uncluttered design. It is crystal clear and scratch resistant visionary glass. These mugs are made of borosilicate. It is microwave safe, food grade safe and freezer safe. Non porous glass will not absorb stains or odours. These are dishwasher safe and are very easy to clean, so stop your worries of cleaning the stubborn dirt that settles down at the bottom of your mugs. This is definitely a must have addition to your glassware collection.