Most of the important properties of an emulsion depend on the type and amount of emulsifier used. Emulsifiers are divided into two categories: anionic and cationic emulsifier. Anionic Type: In which the bitumen particles are negatively charged and the emulsifier is fatty acid metallic soap. These suitable for use with calcareous aggregates like limestone. Cationic type: In which the bitumen particles are positively charged and the emulsifier used is a long chain amine. These are suitable for use with siliceous aggregates like quartzite, sandstone, granite etc. Bitumen emulsions are classified based on how quickly they set, along with their electrical charge. Based on the precise mix of ingredients, an emulsion bitumen may be designed to be rapid-setting (RS), medium-setting (MS), or slow-setting (SS). Cationic emulsions are designated with a letter C in front of the emulsion grade, while anionic emulsions are not given an extra letter. The complete list of emulsion grades is shown in the table below