First Children's Encyclopedia by Dorling Kindersley - page 253

251
Rock and minerals
Mineral mixtures
Granite rock is
made up of different
coloured minerals. The
black mineral is mica,
the pink is feldspar,
and the grey mineral
is quartz.
Feldspar
is used for
glazing
ceramics.
Mica
is
ground up
and used
in paint.
Quartz
can also
occur as the
gemstone
amethyst.
Crystals
Minerals usually form crystals.
Crystals have a number of flat
surfaces. The largest crystals
form when minerals in magma or
trapped liquids cool very slowly.
Halite
Salt is the mineral
halite. We add it to our
food for flavour.
Quartz
from sand is used
to make the silicon chips in
calculators and computers.
Kaolinite
is used to make
crockery. It is also used to
make paper look glossy.
Illite
is a clay mineral
and is used in terracotta
pots and bricks.
Mica
is used to make
glittery paint and
nail polish.
Graphite
is the “lead”
in pencils. It is also
used in bicycle brakes.
Pumice is filled with air bubbles, so some pieces can float.
What is a mineral?
A mineral is a solid that occurs naturally.
It is made up of chemicals and has a crystal
structure. Minerals are everywhere you look.
We use minerals to build cars and computers,
fertilize soil, and to clean our teeth.
Rock salt
is a mineral that is
spread on roads in icy weather.
It makes the ice melt.
Rhodochrosite
is a rose-coloured
gemstone used
in jewellery.
Quartz
stalactites
form in caves
over thousands
of years.
Minerals in your
home
1...,243,244,245,246,247,248,249,250,251,252 254,255,256,257,258,259,260,261,262,263,...306