What is red mercury? It's a fabled substance that might be used to produce nuclear weapons, ward off evil spirits, or help you find treasure, depending on who you ask. There is no real proof that red mercury exists, except perhaps as cinnabar or vermilllion (HgS) or mercury(II) iodide, either of which you can purchase sans sewing machine for a much lower price. Still... if you have your old Singer up for auction at eBay, it might fetch a higher price than you were expecting. If you're considering buying an old Singer, save your pennies until after the scam has run its course.