University of BergenPublished: 05.08.2015 | Author: Haakon Fossen
Amateur geologist Torgeir Garmo at work taking out crystals from the rock. (Karl E. Dalen)
TREASURES IN THE ROCK
Road cuts and blast areas are a joy to rock collectors, even if the disturbance to nature is ever so disfiguring. These are the best kinds of places to hunt for crystals, which otherwise are removed by weather and wind. In the Ågotnes area there are especially many beautiful crystals to be found.
Amateur geologists have long shown an interest in the blasting work in this part of the Fjell municipality. Here, fresh openings along fractures and faults in the bedrock have been shown several places to contain open spaces or cracks that are partially filled with crystals. These occurrenceswere discovered in connection with blasting work along the new road from Bergen toward Øygarden, and through the development of the industrial area at Ågotnes.
The minerals grow when the warm gasses and fluids circulated in the fractures and faults more than 160 million years ago, long before the bedrock had become exposed at the surface. The overheated water can dissolve the mineral material from one place in the earth's crust, and deposit it out slowly as beautiful crystals another place. This can occur a ways down under the earth's crust, where the water is hot enough that it can effectively dissolve and transport the mineral, but not too deep for the open space to exist.
There have been finds of exquisite crystals, among them white feldspar, clear quartz, purple amethyst, green epidote, chlorite and golden pyrite. Especially typical for the region, nonetheless, is fluorite crystals, with their deep purple and occasionally greenish colours. The finest examples have been collected by mineral collectors long ago, but new episodes of blasting will be able to expose new finds. Remember to ask the landowner if you wish to take loose samples. The museum in Bergen has exhibited a number of fine specimens from the Ågotnes area.
Crystals
Bedrock is built up of minerals. Normally, there are not crystal surfaces on the minerals. Crystal surfaces form when a mineral is allowed to grow, without hindrance, from the surrounding bedrock. Then, shapes that we call crystals protrude out. The different types of minerals each form their own distinctive crystal shape.
Amethyst (uppermost), fluorite (middle) and quartz crystal (lowermost), all from Ågotnes. These specimens are exhibited in the Bergen museum, in the Natural History Collections. (Svein Skare)
Quarry at ågotnes
In 1923, the Bergen Port Authorities began to mine wharf stone from Tranevågen north of Ågotnes. Most of the 15-20 men who worked there were the port authority's own people. This work continued on a yearly basis until late in the 1930s, and large amounts of stone were transported to the wharf structures in Bergen.
