Physical Science : Differences Between Rocks & Minerals


Hi, I’m Steve Jones and I’m going to tell
you a little about the difference between rocks and minerals. Here I’ve got a list of
five different types of rock, granite, basalt, gabbro, limestone, sandstone, five different
rocks. Here, I’ve got a list of three minerals, feldspar, quartz and mica. These are minerals
and minerals are chemical substances. In general you can just say they are simple chemical
substances. Quartz is a single substance, silica dioxide, feldspar is a very complex
thing and so is mica, but quartz is a very simple material. But the difference between
the two is that it take minerals to create rocks. So granite for example, contains feldspar.
Granite also contains quartz. Granite also contains mica. These three minerals are found
in granite. The interesting thing is that exactly the same three are also found in,
believe it or not, basalt, all three of them, and also in gabbro. They’re just made in a
different way. The proportion of these minerals in these materials makes them what they are.
So these rocks which are igneous, igneous meaning that they are formed in volcanoes,
igneous rocks. These three igneous rocks are all from one make up of feldspar, quartz and
mica. These are different. These also are rocks but these are sedimentary and the sedimentary
rocks are ones which are formed usually at the bottom of the sea or lake. So they’re
called sedimentary. And what happens for example, in a granite area the granite decays, breaks
up and is washed away in to rivers and it’s deposited on the sea bed and then it’s glued
together by various materials that follow after it until it become sandstone. It’s compressed
and can be very thick in dimensions. So you can get a lot of sandstone because a lot of
material is washed in to rivers. So limestone and sandstone are rocks but they’re formed
in seas and lakes. Granite, basalt, gabbro are rocks but they’re formed from molten rock
that has come from say, a volcano. The minerals, however can be the same in both of these classes
because all that’s happened is the minerals in the granite have decayed and been absorbed
to make sandstone and limestone. Well that’s a rough idea of the difference between rocks
and minerals.

14 thoughts on “Physical Science : Differences Between Rocks & Minerals

  1. Gabbro and basalt are both mafic igneous rocks. They do not contain quartz or mica. Lots of pyroxenes and some olivine, but no quartz or mica.

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