If you already know, we commend you on your knowledge, as for the folks who haven't considered the possibility before now please allow me to explain.
Minerals: Have a defineable chemical composition, shape and structure. Some are useful in biology, usually in bone, blood and muscle function. They are an inorganic composition.
Rocks: Composed of minerals, two or more of them. Limestone, granite and coal are all rocks. Limestone and granite, composed of multiple minerals, and coal has organic origins.
Have a look through our selection of specimens, stop on by, we won't take your visit for 'granite'.