Practising science: Reading the rocks and ecology
Practising science: Reading the rocks and ecology

This free course is available to start right now. Review the full course description and key learning outcomes and create an account and enrol if you want a free statement of participation.

Free course

Practising science: Reading the rocks and ecology

1.2.1 Minerals

A mineral is a solid material, formed by natural processes and with a chemical composition that falls within certain narrow limits. Its constituent atoms are arranged in a regular three-dimensional array or pattern and because of this, minerals form crystals with characteristic shapes.

Although several thousand different kinds of mineral have been discovered, only a few are very common; for example, the mineral quartz, which forms many of the sand grains on a beach or in a desert. Because silicon and oxygen are the two most abundant elements in the Earth's crust, they are the main ingredients of common minerals, and these minerals are known as silicate minerals. They include quartz, whose chemical composition is silicon dioxide (formula SiO2), and a range of others containing additional common chemical elements. A common mineral that is not a silicate is calcite; it has the chemical composition calcium carbonate (CaCO3). Whereas most minerals are identified on the basis of physical characteristics (density, hardness, colour, etc.) calcite can also be readily identified with a chemical test. Calcite reacts with dilute hydrochloric acid, liberating bubbles of carbon dioxide (CO2) gas in a vigorous fizzing froth. The chemical reaction is written as

In words, this equation can be expressed as: solid calcium carbonate (calcite) plus hydrogen ions in the acid plus chloride ions in the acid gives calcium ions, hydroxide ions and chloride ions dissolved in solution plus carbon dioxide gas.

SXR103_1

Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to university level study, find out more about the types of qualifications we offer, including our entry level Access courses and Certificates.

Not ready for University study then browse over 900 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus