IGNEOUS ROCKS TEST
1. Insert the correct word in the gaps using the list below.
Magma forms deep within the earth and as it rises, it …………. Mineral crystals grow in
the cooling magma. As they grow, they lock together to form a crystalline rock. If the
magma crystallises before it reaches the surface, the rock formed is an ………………..
igneous rock. The crystals are ……………….. because the magma cooled……………… If
the magma crystallises after it has flowed out on to the surface, the rock is an ……………
Igneous rock. The crystals are …………….. because the magma cooled……………….
Quickly; slowly; cools; intrusive; large; small.
2. Cross out the incorrect word where there is a choice of two. Fill in the gaps in the
sentences.
a) Granite is an acid/basic rock. The main minerals are ………….., ………………. And
……………
b) Basalt is an acid/basic rock. The main minerals are ………………. And ………………
c) Gabbro is an acid/basic rock. The crystals are larger/smaller than those in basalt.
d) Andesite is a viscous lava. This means that it flows easily/does not flow easily. It is
viscous because it is high in sodium/silica.
3. Draw a diagram to show a sill and a dyke. Label your diagram.
4. How would you expect the crystals in the middle of the dyke to differ from those at
either edge?