Crude oil, as it is extracted from the oil well, is not usable for industrial and automotive applications. For this reason, it has to be subjected to special treatments in specific plants, refineries, where a great variety of products is obtained. Among these products, those that are used for the manufacture of lubricants are the so-called base oils, which can be:
Obtained directly from petroleum. They are the most widely used.
Made with bases that come from complex transformations or synthesis.
Mixture of the two above.
Thus, a lubricating oil is a product formed by a base oil, generally derived from petroleum, and additives (compounds which are incorporated in small amounts into the base oils to obtain a lubricating oil finished with the quality level and type of desired application).
The origin of the base oil is not indicative of lubricant quality. In other words, a lubricant is no better or worse for being mineral or synthetic. The quality of the compounds is determined by laboratory and engine tests that the lubricant must undergo during the design phase.