In order to find out whether the item is a rock or a mineral, numerous tests and observations must be performed. A rock is composed of one or more minerals. If you felt that the item was a mineral, you would observe its color, streak, luster, hardness, cleavage, magnetism, and its reaction with HCl. If you really wanted to, you could perform a taste and smell test, but it would only help with Halite (tastes like salt) and sulfur (smells awful). If you felt it was a rock, you would observe crystal size, its definition of layers, and its grain size. If it has decent sized crystals, it would be Igneous. In that case, you would observe its grain size, its outer appearance, and whether it is felsic (light in color) or mafic (dark in color). If it has very defined layers or contains what appear to be many different rocks, it is sedimentary. Then you would observe grain size and color to identify the rock. If you observe foliation, small grain size, it is most likely metamorphic.
Without experience, it can be difficult to tell the difference between a rock and a mineral. Performing the tests will really help identify the difference. Sometimes, color can be misleading so don’t rely entirely on it, but it can also be helpful so don’t out rule it completely. The luster can help identify a mineral, while the composition can help identify a rock.
No comments:
Post a Comment