sentences: different materials usually have different properties & a mineral is a kind of material ->  different minerals usually have different properties  different minerals usually have different properties & samples of a single type of mineral usually have the same properties ->  different minerals usually have different properties and samples of a single type of mineral usually have the same properties  different minerals usually have different properties and samples of a single type of mineral usually have the same properties & the properties of something can be used to identify / used to describe that something -> the properties of a mineral can be used to identify those minerals