Rocks and Minerals

By David

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.

Hardness

• The softest mineral is Talc.• The hardness of corundum is 9.8

Hardness

• Carnallite has a hardness of 2.5• Opal’s hardness is 5.6• The hardness of obsidian is 7

Color

• Some minerals come in more than one color.• This is because minerals can contain

impurities.

Color

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

Color

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

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

Transparency

• Diamonds, chalcanthite, quartz and rubies are transparent.

• Obsidian is opaque