Minerals: Building Blocks of
Rocks
Minerals
Minerals are the pure, naturally
occurring building blocks of rocks
 Differences in rocks are due to
different minerals
 All minerals are non-living, but a few
contain minerals that were living
things – example chalk
 Minerals are used in our everyday life

Minerals are Crystals
All minerals are pure crystals
 Crystals have regular geometric
shapes because they are made up of
tiny particles connected in a
repeating pattern

 Cooled
slowly = large crystals
 Cooled rapidly = small crystals
Identifying Minerals
Lustre – shininess of a mineral
 Cleavage – describes the way the minerals
split into smaller pieces
 Hardness – describes how resistant a
mineral is to being scratched
 Colour- describes the appearance of the
mineral

 Not
always reliable
Identifying Minerals

Streak – the color the minerals leaves behind
when ‘streaked’ across unglazed porcelain tile

Many have to be crushed to powder to determine
their streak color
Magnetism – 2 minerals, magnetite (strongly)
and pyrrhotite (weakly), have magnetic
properties
 Density – mass per unit volume of a substance
