mineral of earth crust

               mineral:a solid material of earth crust with a definite composition.

                          luster:the way light bounces off a mineral surface.

      streak:the color of the powder left when a mineral is rubbed againt a hard, rough surface.

                            hardness:how well a mineral resists scratching.

                     cleavage:the tendency of a mineral to break along flat surface.

                                ore:a mineral containing a useful subtance.

                             gem:a mineral valued for being rare and beautiful.

nonrenewable resource:a resource that can not be replaced within a short period of time or at all