Long before Europeans first settled in New Zealand the Maori used rocks and minerals. The most prized mineral was pounamu, also known as jade or greenstone. Greenstone occurs in the Southern Alps of the South island and is found as boulders in the rivers of the region.

The Maori recognised many different types of greenstone, and those of high quality were especially valued. Pounamu was used to make ornaments and weapons, and was traded throughout the country.

Obsidian, also known as volcanic glass, is a hard fine grained rock that breaks to make sharp edged cutting tools. Obsidian occurs most commonly in the active volcanic region of the North Island, and was also widely traded.

Maori used fine grained rocks of many types for making axes, adzes and weapons. Before greenstone was discovered baked argillite was quarried from sites in the Marlborough Sounds and Nelson and used by Maori to make tools and weapons.

Tools were sharpened on grinding stones made of course sandstone. These have been found in many parts of the country. Pigments were made from white and coloured clays and sulphur.

European settlement of New Zealand began early in the 19th century. By 1830 coal had been discovered in Otago, followed by gold in the 1840s. Coal and gold were the main mineral products of early European New Zealand, and they remain important today, although aggregates now have a similar value.

Minerals are essential to everyday life. Everything around us that has not been grown has been mined from the earth. Minerals are used to make houses, buildings, roads, dams and power stations. They are also used to make and supply almost everything we use each day. Your television and computer, toaster, toilet and toothbrush are made from minerals.

A mineral can be defined as a chemical substance of inorganic origin that has formed naturally. Under this definition water is a mineral, but coal is not, as it formed from vegetable material. Coal is usually included in any consideration of mineral production and mineral resource summaries because it is produced by mining.

Minerals are made up of atoms. The 88 naturally occurring types of atoms are called elements. These elements combine in various ways to form more than 10,000 known minerals. Only 12 elements and fewer than 100 minerals are relatively common.

The eight most common elements in order of decreasing abundance are:
oxygen, silicon, aluminium, iron, calcium, sodium, magnesium and potassium.

These eight elements make up nearly 99% of the earth's crust. The most common minerals in the crust of the earth is quartz, which is a crystalline form of silica. (Si02). Other common minerals are feldspars (which contain aluminium, sodium, potassium, calcium and silica) and calcite (calcium carbonate).

Most rocks are made up of a number of minerals. Sandstone, for example, consists of grains of sand that have been welded together by heat and pressure after burial. Sandstone is usually made up of grains of quartz, feldspar and other minerals such as magnetite.

There are three main types of rock: sedimentary, igneous and metamorphic.

Sedimentary rock is formed as layers of material are deposited in low lying areas. Often sedimentary rock contains broken or weathered pieces of other rock. Over millions of years the layers harden and form solid rock. Sometimes fossils are trapped between the layers. Limestone is a good example of a sedimentary rock.

Igneous rock is formed when molten material cools and solidifies. The basalt found in the Mt Wellington quarry in Auckland is an igneous rock. Obsidian - volcanic glass - is also an igneous rock, so is pumice. New Zealand's volcanic past means we have lots of igneous rock types.

Metamorphic rocks are changed from one rock type to another by very high temperatures or tremendous pressure. Metamorphic rocks rocks can be formed from igneous or sedimentary rock, or even other metapmorphic rock. When limestone is heated it alters to form marble. Slate is a metamorphic rock. It is often used for floor tiles.

In New Zealand we use large large quantities of minerals per person compared to the rest of the world, and we are among the world's largest consumers of fertiliser minerals.

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