The conventional types (excluding the complex soap greases have a smooth buttery texture and are water resistant, with dropping points around 90- 100 ºC. They are water stabilized, that is , the water is present in the soap crystals as water of crystallization. The optimum amount of water varies considerably with the type of formulation, fatty material and mineral oil used, but is usually within the range of 0.5 – 1.3% by wt. at high temperatures the water is gradually lost and the soap structure is weakened. Consequently, calcium soap Greases are restricted to use at fairly low maximum temperatures about 50 – 60ºC. They all turn fluid after exposure to high temperatures and may separate into the oil and soap phases. Only those which contain other stabilizers besides water (e.g. wool grease) will regain their structure on cooling.