Minerals and ores

The idea

The earth's crust is the major source of metals; elements or compounds occurring naturally in it are minerals, and minerals from which a metal can be profitably extracted are ores.

Digging for metals

Miners dig deep into the ground to get metals.

What is the main natural source of metals?

• The earth's crust
• The clouds
• Fresh river water

Crust, minerals, ores

Press Next step.

From mineral to ore

Minerals are the elements or compounds found naturally in the earth's crust. A mineral from which a metal can be profitably extracted is an ore. So every ore is a mineral, but a mineral is called an ore only when it is rich enough in a metal to make extraction worthwhile.

The earth's crust is the major source of metals; elements or compounds occurring naturally in it are minerals, and minerals from which a metal can be profitably extracted are ores.

Notes

The earth's crust gives metals; naturally occurring elements or compounds there are minerals; those from which a metal can be profitably extracted are ores.

Check yourself

Elements or compounds that occur naturally in the earth's crust are called ...

Minerals from which a metal can be profitably extracted are called ...

Which is the major source of metals?

Seawater contains some soluble salts. Which pair is named in the book?

• alloys. An alloy is a homogeneous mixture of metals, or of a metal and a non-metal; the word for naturally occurring elements or compounds is mineral.
• minerals — correct. Yes!
• allotropes. Allotropes are different forms of one element.
• gangue. Gangue is the impurity, like soil and sand, mixed with an ore.
• amalgams. An amalgam is an alloy that contains mercury.
• ores — correct. Yes!
• The earth's crust — correct. Yes!
• The air. The book names the earth's crust as the major source of metals.
• Rain water. The book names the earth's crust as the major source of metals.
• Iron oxide and zinc oxide. The book names sodium chloride and magnesium chloride in seawater.
• Sodium chloride and magnesium chloride — correct. Yes!
• Silver and gold. The book names sodium chloride and magnesium chloride in seawater.