This calls for size 20 threads, an 8 or 9 hook and an 8 inch asbestos mat. Well, we don't use asbestos mats anymore, but one can use the round cork mats sold in the garden section for use under potted plants. Or, using thick cotton or wool, crochet a circle in coordinating background color. As this is meant to be used on a table, using a synthetic wouldn't be too bad, but synthetics would compress with heat and break down too fast and also conduct heat far more that natural fibers, so wouldn't really be the best choice with a truly hot dish. Wouldn't this be cute with a traditional pansy teapot?
UPDATE: RosesNLace at Ravelry has made this as a lovely doily with slight variations.