How is identifying rocks different from identifying the minerals that compose the rocks?

Question

anonymous · Answer

-One of the main methods of identifying rocks is by their method of formation. Igneous rock from melt; metamorphic rock from heat/pressure;sedimentary rock from lithification of sediment or precipitation. Then add in the myriad of possible combinations and percentages of minerals that may comprise the rock, and sometimes the identification of a rock can be a daunting task. 
-Minerals are identified by their chemical composition, their crystalline structure, their specific gravity, hardness, streak, and other physical properties.