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Hardness, the resistance which the smooth surface of a mineral has to being scratched, is an important determining factor in mineral identification. The Moh's Hardness Scale, which was developed over a century ago, is set up so that any mineral can scratch all those beneath it in the scale, or can be scratched by those above it in the scale. The scale ranges from 1 (softest) to 10 (hardest). For example, calcite has a Moh's hardness of 3 and can thus scratch gypsum (hardness of 2) and talc (hardness of 1).
Our Moh's Hardness Scale includes 9 minerals mounted on a card matched to their corresponding Moh's hardness. Diamond, which has a Moh's hardness of 10, is not included. Be sure to check out our selection of Rocks & Minerals, so you can start testing soon.