The Wonderful World of Icelandic Rocks and Minerals

Update: Read about the latest eruption on the Reykjanes peninsula here. More information about eruptions and volcanoes in Iceland can be found here as well.

Iceland was formed roughly 20-25 million years ago by volcanic eruptions. It is a volcanic island with many spectacular geological features. Iceland has about 30 active volcanic systems, and more than 100 inactive ones. Volcanoes might stand out the most, but on a much smaller scale, Iceland is home to many interesting and beautiful stones, rocks, minerals and crystals. In this article, we will tell you more about Iceland’s rocks and minerals.

Since Iceland consists for 90% of basalt, let’s talk about this rock type first. Basalt is a dark grey or black rock, sometimes having a columnar structure, formed by solidification of magma. It can be dense or fine-grained and usually consists of plagioclase, augite and magnetite. Basalt is not unique to Iceland. It makes up most of the world’s oceanic crust, and it’s found in big quantities in Greenland and Scotland, and many more places. In Iceland, basalt columns are a popular tourist attraction. Reynisfjara beach on the south coast is one of the locations people flock to for taking pictures of the impressive basalt columns, and Svartifoss, a waterfall dropping down black basalt columns, is another one. Be sure to check these sites out when you’re in Iceland.

One Icelandic mineral contributed to science in several ways. We are talking about Iceland spar, a pure calcite crystal. Even though Iceland spar can be found in other places than Iceland, it got its name because it was first brought to Europe from Helgustaðir in East Iceland in the 17th century. The supply in Helgustaðir was mined extensively up into the 20th century. The crystals from Iceland were used in optical instruments like petrological microscopes. The double-refraction property of calcite played an important role in studies of light as a wave. Iceland spar was studied by Christiaan Huygens, Isaac Newton, George Stokes, and William Nicol, among others. These days, synthetic materials have taken over and demand for calcite has ceased. The mine at Helgustaðir was placed under official protection in 1975, prohibiting calcite being removed from the area.

In the age of settlement, Iceland spar was possibly used for navigational purposes. Vikings might have used an object called a sólarsteinn (sunstone) to locate the direction of the sun in cloudy skies and twilight conditions. By looking through Iceland spar with the naked eye, the direction of the sun can be identified to within a few degrees. It’s likely that Iceland spar is the same as sólarsteinn. Iceland spar has also been found inside an Elizabethan ship that sank in 1592, pointing towards the fact that the crystal was used to help with navigation long after the widespread use of the magnetic compass.

Is there life on Mars? Well, we don’t know yet. But we do know a lot about Mars’ surface, partly because of a rock that is commonly found in Iceland: palagonite. Palagonite is formed in subglacial and subaquatic eruptions. When water turns into steam on contact with hot lava, small fragments of lava react with this steam to form light-coloured palagonite tuff cones. Even though palagonite is found in other places around the world, it is nowhere as common and easy to study as in Iceland. Palagonite has sparked interest around the world, because similar rocks appear to exist on Mars. Properties of Martian dust match best with a sort of palagonite. Since water is involved in the process of forming palagonite, it has been used as evidence for the existence of water on Mars.

If you want to see Icelandic rocks and minerals, head to Petra’s Stone Collection in Stöðvarfjörður, East Iceland. This stone museum is founded by Ljósbjörg Petra María (1922-2012), known as Petra, who started collecting stones and rocks in the area and displaying these in her yard. Over the years, her collection kept growing and growing, and visitors in the area showed a lot of interest. After a while, her house was turned into a museum showcasing the best specimens. There you can probably find some of the many rocks and minerals not mentioned in this article, like Icelandite, zeolite, rhyolite, obsidian, tholeiite, olivine tholeiite, gabbro, plagioclase, augite, olivine, magnetite and apatite. There is a coffeehouse at the museum, called Café Sunnó, that is open during summertime and has coffee, sandwiches and soup on offer.

You are not allowed to take rocks or minerals from national parks and protected areas. Removal of Iceland spar, and stalactites and stalagmites is strictly forbidden. You are also not allowed to take rocks and minerals from someone’s land. Most of the land in Iceland is privately owned, so this means you are not allowed to take rocks and minerals from Iceland back home. If you are looking for a nice souvenir, head to one of the many souvenir shops selling products made with lava rocks.

Do you want to read more about Icelandic rocks? Read this article about Iceland’s unique rock formations.