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?
All our geology articles
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
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.
