Agate imported from the remote caves of…..no, just kidding; The Michael Wainwright USA Borealis collection is actually clay with a really cool crystal glaze, finished with 24k gold or platinum, and handmade in Western Massachusetts by Michael himself. The collection is finished with a reactive glaze that fires slightly differently every time, which is one of the beauties of this collection. It is food-safe and safe to cut on. Hand washing is recommended, not for use in a microwave. 7″ x 8″.