Solid Black Walnut Wood coaster base for crystal lamps are 1 inch thick. They are not stained this is their natural color, and they are finished with mineral oil. The round bases are 4 inches diameter and fit perfectly with my Raw Selenite Skyscraper Crystal lamps. The square bases are 4 inches by 4 inches and fit with many crystal lamps. 
The solid wood base is a nice way to display your crystal lamps and to provide insulation for the heat they can generate. These bases were handcrafted in New York by my Dad, Larry McKeough, who has been woodworking for over 40 years and is a highly skilled craftsmen.