What are Minerals? | What are Mineral Properties? - GeologyTo meet the definition of "mineral" used by most geologists, a substance must . For example: the mineral halite (known as "rock salt" when it is mined) has a.definition of minerals in rock,Rocks and Minerals - OGReAt the base of all minerals and rocks are the earth's elements. . From this basis, we can define all rocks as composed of one or more minerals. A rock is.