Mineral sulfur is a widely used ingredient to form cross-links between the rubber chains in the vulcanization process. During compounding, a high elastic state of sulfur at temperatures between 40°C and 70°C promotes elongation of its particles and, next, breaking these thin and weak needles into pieces. This increases the surface area of particles and, after melting, creates conditions for intensive diffusion of sulfur into the rubber matrix, which helps to equalize the distribution of sulfur in cured rubber. Sulfur is relatively uniformly distributed in the bulk of rubber compound. However, during storage of rubber compounds, a thin layer of sulfur is observed on their surface (a bloom). This detrimentally affects processing and has an influence on cured rubber properties in use. Up to 40°C, the concentration of bloomed sulfur increases as the storage time of a rubber compound is prolonged. For temperatures above 42°C, bloomed sulfur disappears gradually. The eutectic alloy of sulfur/stearic acid should play an important role in the disappearance of a bloom layer from the surface of a rubber compound stored at a temperature above 42°C. This is because the melting point for this eutectic, about 46°C, is very close to that at which the change in mechanism of blooming was noticed. Under this condition, sulfur, as a eutectic, is in a molten state; due to this, it can diffuse into the polymer matrix. Formation of a eutectic is possible if molten particles of the curing system, containing sulfur, accelerator(s), stearic acid, and zinc oxide, will meet each other inside the rubber matrix during the last stage of compounding.