White mineral oil is the highly refined mineral oil, and is composed of saturated aliphatic and alicyclic nonpolar hydrocarbons. White mineral oil is biologically and chemically stable, and doesn't support pathogenic bacterial growth. White mineral oil can resist moisture, extend, soften, smoothen, and lubricate[1].
[1]. J F Nash, et al. A toxicological review of topical exposure to white mineral oils. Food Chem Toxicol. 1996 Feb;34(2):213-25.