Newsademic British English edition 260

in e r a l
 
catalogue
More than 5,200 minerals have been 
recorded. Some are very common. 
Others can be found only in a few 
places. Mineralogists, or scientists 
who study minerals, from the USA 
have completed a new mineral cata­
logue. It lists the Earth’s 2,550 rar­
est minerals. Each exists in fewer 
than five places.
Minerals and rocks are different. 
Minerals are inorganic substances 
that occur naturally. They are made 
o f non-living particles. Minerals are 
usually solid and have a geometric 
shape, or crystal structure. They 
are the same substance all the way 
through. Rocks are made o f minerals 
but minerals are not made of rock.
All rocks contain at least two miner­
als. So when two or more minerals 
come together they form a rock.
Cakes are made from a number 
o f ingredients. If a rock were a cake, 
its ingredients would be minerals. 
Quartz is the Earth’s most abun­
dant, or common, mineral. The most 
widespread rock is basalt. N owa­
days, about 100 new minerals are 
found every year.
Exam ples o f m inerals
A mineral can be made from one 
chemical element. Yet most consist 
o f two or more. Diamond is a min­
eral. It is made from carbon, or one 
element. Diamond is also the hard­
est natural substance in the world. 
Fluorite, another mineral, is made 
from a mixture, or compound, of 
calcium and fluorine. Gold is one 
o f the most valuable minerals. It is 
very soft.
Silicates are minerals that con­
tain oxygen and silicon. About 
90% o f the Earth’s crust is made 
from silicates. Nearly all the min­
erals in the crust are made from 
eight elements. These are: oxygen, 
silicon, aluminium, iron, calcium, 
sodium, potassium, and magne­
sium. As well as quartz, other 
common minerals are: feldspar, 
bauxite, cobalt, talc, and pyrite. 
Gems are pieces of rare minerals, 
which are cut and polished. Cut 
diamonds, emeralds, rubies, and 
sapphires, are examples.

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