D. Unique to that mineral. Each type of mineral has a chemical composition that is unique to that mineral.
Every mineral on the face of the Earth is different, otherwise, we'd call every substance a name solely based on color or shape. There are hundreds and thousands of different minerals in and on the Earth. Now, the way we separate these minerals so that we can keep track of them, is by checking their chemical composition. For instance, you could find two red rocks that look very similar to each other, and understandably, you could mistake this as the same mineral. However, if you were to check their chemical composition by any number of various tests, you would find that the two red rocks are actually different minerals. In this example they are any ways, you could very well find two red rocks that are the same mineral, but with out testing the chemical composition, there's no real way of knowing. The more tests you have with the mineral, the better understanding you'd have of that specific mineral to the point where you could classify it as the mineral it truly is. Because of this, we know that scientists classify minerals according to chemical composition, therefore, we now know that minerals all have chemical compositions unique to that specific mineral.
