Mineral wool means fibres mae 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 rock wool, also known as stone 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.