In order to make a ring, you must choose the clay fist. In this case the best thing is to use PMC+ or PMC3 because they are denser than the Original PMC, and can be fired with a kiln for 10 minutes, or with a butane torch that reduces the risk of overheating.The PMC+ is stronger than the others and it is the best choice to make a ring because it resists the everyday stress. It is maybe a little expensive but your piece will never brake.The PMC3 will let you add a stone. Also you must consider the shrinkage rate that is 12% in this 2 kinds of PMC.The final thickness should be at least 1.12 mm or thicker to be possible to polish it.If you will experiment with the PMC, I suggest you to buy the 45 gram lump package, because to know the properties of this clay it is good to let your imagination flow and use it all making more pieces. Then, analyzing the shrinkage rate, your ring size and the thickness you want, you can determinate how much PMC you will need for other rings.