|The hardness scale was developed in 1812 in order to make comparison of different types of rocks and minerals. The scale ranges from 1 being talc, to 10 being diamond. When we scratch rocks with different things we can determine its hardness.|
Should a finger nail be able to scratch the diamond or should the diamond be able to scratch a finger nail? Explain.
Look at the scale and decide what two things would be able to scratch glass. Explain your answer.
What should a copper penny be able to scratch? Why do you think so?
Should a finger nail be able to scratch glass? Why or why not?
If you were to test a piece of chalk and decide where on the scale it should be, what could you use to do a scratch test on it? (Chalk used to be made of sedimentary rock—soft limestone). What number might chalk be? Test it and find out if you are correct.
*Hardness is one of the properties of rocks and minerals.