There are mineral based, ash based and completely synthetic baes for oils.
For many years Mobil was ash based, and Only Royal Purple was 100% $ynthetic.
Pure Synthetics are more durable.
Worried about your rear end, or trans ,or engine?
Put some " Motor Kote" in your oil.
Extreme testing has proved its worth.
Reduce friction.
https://m.youtube.com/watch?v=88vwUwa3igQ