There’s one very important thing that all rocks – from the hardest to the softest – have in common…
…All rocks are solid mixtures of minerals – sometimes only one or two minerals, but usually several.
The rock Granite, for example, is made of three minerals:
Don’t worry if these words don't mean anything to you - we’ll tell you more about them later.
Minerals are solid mixtures of chemicals. There are roughly 3,500 minerals, but only about 100 are common. The rest are rare – often rarer than gold. Each year, around 20 new ones are discovered.
Minerals are formed from chemical ingredients called elements and are affected by things like temperature and pressure as they develop.
Elements are made of only one substance. Oxygen, for example, contains only Oxygen. When different elements combine with each other they form compounds.
Some minerals, such as Garnet, form over thousands of years as heat and pressure gradually alter a rock. Olivine crystals, on the other hand, can grow very quickly.
Groups of minerals grow or cement together in different ways to form rocks. The Earth’s crust (surface layer) is made up of these rocks.
Rocks and minerals have formed since the beginning of time, and are still forming today. By studying the world’s rock solid evidence, scientists have been able to calculate the age of the Earth and find out about the great events that have shaped our planet.
Like people, and their fingerprints, no two minerals are exactly alike. Each mineral has a unique set of properties that can give it value or make it useful.
Here are six of the main properties we use to identify and classify minerals.
Don’t worry if some of these words sound a bit foreign to you – it just means you haven’t visited the Quarryville Laboratory yet.