Mineral Oil,as the name suggests,comes out of the ground,and usually results from one of the refining processes of Crude Oil.The hydraulic systems in the Navy fighter-jets that I worked on used a mineral oil as the hydraulic fluid, namely "OM 15" in British Navy terminology,the "OM" standing for Oil,Mineral, (naturally).It was also VERY good for cleaning aircraft with----strictly forbidden,but we all did it !! Other oils in common use are obtained from vegetable sources,ie Rapeseed,Grapeseed,Walnut,Sesame, et al.In earlier times,of course,the oil from the head of a Sperm Whale was considered to be the finest lubricant available,and was,I believe,used with early sewing-machines.