They are both hydrocarbons derived from petroleum, but they are quite different from each other.
Petroleum ether is a petroleum fraction consisting of
It boils in the range 35 °C to 60 ℃ and is commonly used as a laboratory solvent.
The name "ether" is used only figuratively because the mixture is almost as volatile as diethyl ether.
Mineral oil is a colourless and odourless mixture of petroleum hydrocarbons with a boiling point of about 310 °C and carbon numbers ranging from
It is commonly used as a lubricant and laxative and as an ingredient in lotions, creams, ointments, and cosmetics.