The Earth is estimated to be 4.6 billion years old. Dust and gas from a big explosion was driven together and formed the Sun and the planets. After that point there is a complex history of geological processes that lead to the Earth that we know today.

Some of these processes are slow and quiet like a river that year after year carry sand grains to the coast. When these grains are building on top of each other the sand layers get thicker and thicker and the deeper part of the layers will, due to high pressure and temperature, slowly start to become a hard sedimentary sandstone.

An even more slow and quiet process is that of organisms that use calcium carbonate from the seawater to build a protecting shell around themselves, like corals and many other types of animals and small algas. These organisms can build up large layers and if they are buried under thick piles of sediments they start to build harder rocks like limestones. If the sediments are buried deeper the original minerals starts to reform, and create a new rock called marble.

The Norwegian Rose is interpreted to be part of a carbonate shelf close to a tidal flat. In that carbonate shelf there was a big river that carved out a deep channel, and in that channel there was deposited big and small blocks of rock which eventually formed the different kind of textures seen in the quarry.

Other processes are rapid and violent like volcanic eruptions, earthquakes, and tsunamis. In these processes new landform and mountains is created in very short time.

The Earth is an active planet. The hot center of the inner part of the planet gives birth to plate movements, volcanism, earthquake, land rise and mountain ranges. We are living on the thin outer crust of the planet which is only 5 to 70 km thick. This thin crust consists of several moving plates floating like ice bergs on the water. They collide and break up and move on.

Click on this to se different types:

Granites are classified as a magmatic rock, which means that they are formed by crystallization of melted rock mass. A melted rock mass, formed deep down in the Earth’s crust, is lighter than the colder rock above and will start to move upwards in the crust. If the rock mass comes all the way to the surface there will be a volcanic eruption and a volcano is created. If the rock mass can’t make it to the surface it will crystallize and stop somewhere in the Earth’s crust and form a magmatic rock.

When a magma is cooled down minerals start to form. These minerals may consist of many different colours, textures and sizes due to the difference in chemical composition of the melted rock mass, how fast it cools down, in what environment is formed in and other things.

This brings us to the unique rock in the Larvik area 120 km south of Oslo, the capital of Norway. The area around Oslo has a very special geological history, and therefore consists of very special rocks. One of the rocks is named Larvikite, after the name of the local town. Larvikite was named Blue and Emerald Pearl as commercial terms. The Oslo Rift was formed around 300 million years ago, and is an equivalent to Africa’s Rift Valley today.

The Oslo Rift was formed during more than 70 million years. One of the first and deepest rocks that make up the Rift was the Larvikite. They were formed several km under the surface. The geological term for Larvikite is monzonite with low amount of quartz and more than 80% of alkalifeldspar.

Now 300 million years later the erosion, specially the many glaciers consisting of thousands of meter of ice, has moved all the rock above the deep Larvikites, and exposed their beauty for us to make use of in many exciting ways.