This Sommelier's Wine Bottle Coaster is Black Marble and has a recessed well, or cork rest (7/8" diameter x 3/4" deep) in the rim. A freshly extracted cork can be set vertically in the cork rest, preventing tablecloth stains. To keep with tradition, the cork is easily available, next to the bottle, for examination. Black felt base. Natural cork mat inside. The offset bottle well: 4: diameter, 1" thick.