Mineral wool, means fibres made from minerals or metal oxides, be they synthetic or natural. In industry use, MMMF (man-made-mineral-fibres) generally refer to synthetic materials. This includes fibreglass, ceramic fibres and also rockwool, also known as stone wool, and rock wool. Mineral wool is an inorganic substance used for insulation and filtering. A common mistake is to believe that fibreglass and ceramic fibres are NOT mineral wools, but they are by virtue of their consisting of minerals or metal oxides.