When evaluating Soapstone Talc, the most critical factors are whiteness (brightness), particle size (mesh), and chemical purity. For high-end applications like plastics or coatings, a whiteness level of 90% or above is preferred. Particle size should be selected based on the end-use; for example, 325 mesh to 1250 mesh is common for industrial fillers. Additionally, ensure the Magnesium Oxide (MgO) content is typically between 30-32% and Silica (SiO2) is around 60-62% to guarantee authentic mineral properties.