a. Eminently rich lime:
It slakes rapidly. It consists of less than 5% of impurities such as silica and alumina (in clay form) and high %age of CaO. It is slow in setting and hardening and setting depends on CO2 from atmosphere, therefore rich lime is used for plastering but not mortar making. It may be used for inferior and temporary structures.
B. Lean and poor lime:
It contains more than 5% clayey impurities and other impurities like silica, alumina, iron and magnesium oxides, exceeds 11%. Due to large amount of impurities it slakes slowly. It also sets and hardens very slowly. It is used both for plastering and mortar making for inferior class of work.