Using the Mohs Scale of Mineral Hardness

Equipment and materials

Directions

Put on safety glasses before you begin. Small pieces can break off during testing.
Place one mineral on a tray or plate. Hold it steady on a flat surface.
Try to scratch the mineral with your fingernail using light pressure.
Look closely for a real scratch, not a mark that rubs off.
Write down whether the fingernail scratched the mineral or not.
If the fingernail does not scratch it, test with a copper coin.
Record the result after each test tool.
If the coin does not scratch it, try a steel nail or paper clip.
Use glass or tile only if the mineral has not scratched yet.
Compare which tools scratched the mineral and which did not.
Use the Mohs scale list below to find the hardness range.
Repeat the steps for each mineral sample.

Mohs scale levels and how to place the mineral

Level 1: If a fingernail easily scratches the mineral, it belongs near level one.
Level 2: If a fingernail scratches it, but barely, it fits between levels one and two.
Level 3: If a copper coin scratches it, but a fingernail does not, it belongs near level three.
Level 4–5: If a steel nail scratches it, but a coin does not, it fits in this range.
Level 6: If the mineral scratches glass, it belongs at level six or higher.
Level 7–8: If it scratches glass easily and resists a steel nail, it fits here.
Level 9–10: If it scratches all tools and is very hard to mark, it belongs at the top levels.

Notes, variations, and safety tips