The temperature on the moon is 1000C and -1500C during day and night time respectively. Oils and greases cannot withstand such temperature changes but graphite is unaffected within this temperature range. Hence, it acts as good lubricant on the surface of the moon.
Graphite is the mineral form of carbon. Veins of graphite occur in limestone due to the presence of organic materials. Graphite is a soft mineral and occurs in either lump or flake form. Graphite is the only non-metal element that is a good conductor of electricity. Crystal structures rarely occur and easily break down. This is the reason for the material’s greasy feeling despite being a dry lubricant.