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A feldspar quarry in India

A feldspar rock quarry in India

Is feldspar rare?

Feldspar is a very common igneous rock. More than half of the Earth‘s crust is made of feldspar.

What are igneous rocks?
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What is feldspar made of?

When molecules of aluminum, silica and oxygen get together with potassium, they combine to make the rock feldspar.

Aluminum atoms
Silica atoms
Oxygen atoms

Feldspar and quartz make granite

Feldspar often combines with another rock called quartz. That makes a much harder igneous rock called granite. Granite was very useful to people. For example, in ancient Egypt, artists carved statues out of granite. People also use granite for buildings.

What is quartz?
What is granite?
Egyptian sculpture

Feldspar and pyroxene make basalt

Or, if feldspar gets in contact with another rock called pyroxene, those two rocks combine to make basalt. Since the Stone Age, people have used basalt for grindstones. Basalt is a very hard rock too. One of the earliest trade goods was basalt for grindstones, carried down rivers or on donkeys.

More about basalt
Basalt grindstones
Early African economy

Feldspar close up: vertical planes, pale pink-orange

Feldspar close up

Feldspar becomes kaolin clay

When feldspar is in contact with wind or water, the wind and water gradually grind the feldspar down into tiny grains that become one kind of clay called kaolin. Kaolin is the extremely fine, white clay that Chinese porcelain is made of.

Why does the wind blow?
What is kaolin?
More about Chinese porcelain

Learn by doing: finding different kinds of rocks
More about granite
And more about basalt
More about igneous rocks

Bibliography and further reading about rocks:

More about igneous rocks
And more about volcanoes
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