Natural stone

Since the origin of mankind, stone, in addition to wood and bone, has been used for tools and weapons. Metals were discovered much later. From the flint axes of prehistoric times and marble images dating back to Greek and Roman times, up to the modern façade coping of office premises, mankind has valued natural stone and has further developed its processing possibilities.

In many towns and villages, the architecture reveals the connection with the rocks available in the residential area. Despite steel and concrete, natural stone retains its importance. Indeed, natural stone is increasingly being used in interior and exterior design, and in recent years has appeared more frequently in private houses.

Natural stone is a collective name for all types of stone which appear on our earth. In order to make a distinction between different types of rocks, they are categorised in three main groups, according to their origin:

• Igneous rocks
• Sedimentary rocks
• Metamorphic rocks

Igneous rocks

Igneous rocks are formed by the cooling and solidification of liquid magma.

This cooling can take place in, as well as on, the earth's crust. With the cooling in the earth's crust (magma) abyssal rocks are formed. When the liquid rock exits the earth’s crust (lava) and cools volcanic rocks are formed. As an intermediary form, magma can also solidify in splits and separation layers in the earth's crust. These rocks are called intrusive rocks.

Abyssal rocks

These rocks are gradually cooled and formed under great constant pressure.

This forms large granular rocks with crystals clearly visible to the naked eye. Examples of abyssal rocks are granites and gabbros.

Volcanic rocks

When magma appears at the earth's surface we call it lava. The lava cools relatively quickly and, as a result, solidifies later than abyssal rocks. These rocks contain almost no crystals and often have a fluid structure. Due to the escape of gas during the volcanic explosion, these rocks often contain small air pockets. Examples of volcanic rocks are basalt and lava.

Intrusive rocks

Intrusive rocks form an intermediary between volcanic rocks and abyssal rocks. They often have the properties of both rocks. Intrusive rocks always have a double name. An example of an intrusive rock is basalt lava.

Sedimentary rocks

Sedimentary rocks are formed by depositing clay, sand or chalk layers which are subsequently petrified. These rocks are always present in rivers and seas.
These deposits originate from eroded natural rocks or the chalk from crustaceans.
Examples of sedimentary rocks are sandstone, slate and limestone.

Metamorphic rocks

The movement of the earth's plates, among other things, causes mountains to be formed. This movement causes extreme pressure and temperatures. As a result, the existing rocks undergo metamorphosis by which the appearance as well as the properties of the rocks change.
Examples of Metamorphic rocks are limestone>marble, sandstone>quartzite en granite>gneiss.