Semi Precious Stone Coasters. Agate A Distant Cousin Of Sand, Is A Semiprecious Stone That Occurs In Volcanic And Metamorphic Rocks. With Its Natural Wavy Bands Of Purple On A Smooth Cool Texture, This Set Is Truly A Handmade Beauty. Its Dense Crystals Make It Hard And Scratch-proof, Creating A Perfect Set Of Coasters For Your Home. Esplanade Is A International Brand Of Traditional Products Which Has Been Handcrafted For Modern Use.