1. Rocks and Minerals By David

2. Hardness Friedrich Mohs invented the Moh’s scale to measure how hard is a mineral depending on how easy it’s to scratch it. The scale goes from 1 to 10.

3. Hardness The softest mineral is Talc. The hardness of corundum is 9.8

4. Hardness Carnallite has a hardness of 2.5 Opal’s hardness is 5.6 The hardness of obsidian is 7

5. Color Some minerals come in more than one color. This is because minerals can contain impurities.

6. Color Diamonds can be transparent, black, etc… Obsidian can be black, brown or green Corundum is purple.

7. Color Carnallite is orange Sapphires can be blue, pink, yellow, green, etc.

8. Transparency It defines how much you can see through a mineral. Translucent: if light can pass through the mineral. Opaque: when light can’t pass through the mineral. Transparent: when minerals are clear and see- through

9. Transparency Diamonds, chalcanthite, quartz and rubies are transparent. Obsidian is opaque