Manufactured by Mitsubishi materials, all three types of precious metal clay (PMC) - PMC Standard, PMC +, and PMC 3 consist of precious metal (silver) in powdered form, a non-toxic organic binder (clay) and water. The differences between the 3 types are firing times, firing temperatures, and shrinkage rates. These variances are the result of differences in the particle size of the metal, and the percentages of the binder within the clay. PMC3 is the newest member of the PMC lineup. PMC3 features similar working characteristics to those of PMC+, but fires at an even lower temperature. With such a low firing temperature, PMC is ideal for use with some natural gemstones, as well as glass, This is the PMC most recommended for use with glass. Also, low firing temperatures means that PMC3 is can be used with more inexpensive kilns, and even butane torches. PMC3 is the most dense, and may crack from time to time. Fire PMC3 at 1290 degrees Fahrenheit for 10 minutes, 1200 for 20 minutes, and as low as 1110 for 45 minutes.