How do you determine what mineral you are holding? By doing a scratch test and comparing your results with those of other mineral and tools. The students had to figure out what minerals they had by scratching them with their fingernails, aluminum nails, and steel nails. They then used the Mohs Hardness Scale to come up with the right answer. Be sure to ask them which mineral is at the top of the scale and which is at the bottom. There are more pictures under the gallery tab.