Curriculum
Science — Second Preparatory
Unit 1: Matter and Energy
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Unit 2: Matter and Chemical Reactions
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Unit 3: Energy Flow in Photosynthesis and Respiration
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Text lesson
Formation of Minerals and Soil
Formation of Minerals and Soil
Hardness and Mohs’ scale
Hardness and Mohs’ scale
- The hardness of a mineral is measured by its ability to scratch another mineral.
- Scientists use Mohs’ scale, which ranks ten minerals from the softest to the hardest:
| Rank | Mineral |
|---|---|
| 1 | Talc |
| 2 | Gypsum |
| 3 | Calcite |
| 4 | Fluorite |
| 5 | Apatite |
| 6 | Orthoclase |
| 7 | Quartz |
| 8 | Topaz |
| 9 | Corundum |
| 10 | Diamond |
- A mineral that scratches another mineral in the table is harder than it.
- Quartz scratches calcite, but calcite does not scratch quartz.
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