Some things I have learned about rocks

The hardness scale only goes to 10. You can use the hardness scale by scratching a rock to see how easy it is to leave a mark on it. If it doesn't have a mark, then it is somewhere around 8-10. If it leave a big mark, it is 1-5.

You can use your finger nail or, if you don't want to scratch your nail, you can use a coin like a dime or penny. #rockidentification