What is molybdenum? Molybdenum Powder (Moly) is a dense metal powder that is known for its wear resistance, and strong electrical conducting properties. Screening moly powder can be a tricky process using a conventional screener. Like any metal powder, it is very dense and this can kill the energy inside a screener, making the separation very difficult. The shape of the powder is typically not spherical and this needs to be considered when determining the right approach to sieving moly powder.