Vikings and Rocks: Icelandic Spar

One of our club members Jamie Erickson wrote this brief article about Icelandic Spar, or Calcite and its connection to the Vikings. Enjoy!

In today’s society, everyone has a slightly different romanticized image of the famous Norse travelers the Vikings. We have pieced things together from movies, books, legends, and family trees… there might even be some historical fact in there somewhere!

Geologically speaking, Vikings were some of the OG’s (original gangsters) of the rock collecting world. They traded amber beads across the world, and they wore precious metals in bands across their arms. We know this is true based on a wealth of evidence in the archaeological record. However, their love for rocks was not limited to cultural aesthetics and monetary values. They also are believed to have utilized what have been called ‘Sunstones’ in the sagas to assist with navigation.

It is thought that Vikings were able to look through a crystal, and use its light polarizing property to be able to locate the position of the sun on a cloudy day. This was important, as with out night stars or the sun, they would not have been able to chart a course at sea.  Light passes though the crystal and exits in two paths, creating a double image of an object. This would make the sun more noticeable on an overcast or foggy day. It could even allow for the Vikings to find the sun in the Arctic when the sun falls bellow the horizon.

Icelandic spar is more specifically a variety of calcite, or calcium carbonate. I will not go too much more into its chemical makeup, as I am no expert in chemistry. It can be found more notoriously in Icelandic mines, the most prominent being Helgustadir. Helgustadir is known to have been mined from the 17^th century into the early 1920s, when it became largely inaccessible due to heavy snow and dumps from former mining activity.  Collecting from Helgustadir was made illegal in 1975, as it became a national heritage site.

Calcite in its broader forms is one of the most common minerals worldwide. Now I know what you are thinking, I too have calcite specimens that are various pastel colors such as orange and blue- Icelandic spar is free of impurities, making it clear. This clear variety is a bit harder to find. Icelandic Spar, in addition to Iceland, can also be found in the Sonoran desert, Mexico, New Mexico, and China. After doing some initial googling, I have found that people are either charging or have paid anywhere from $50-$200 for a piece to add to their collection. 

While historians, archaeologists, and geologists believe that this ‘sunstone’ is likely this variety of calcite, what evidence are they basing their opinion on? Two 13-14^th century Icelandic texts from Iceland describe this ‘sunstone’, and how it was used to fin the sun on a cloudy day. The first text Rauðúlfs þáttr is an ecclesiastical text about Saint Olav, and the second Hrafns saga Sveinbjarnarsonar is about an Icelandic cheiftan who was murdered by an enemy. Several 14-15^th century churches and one monastery also list ‘sunstones’ in their inventories.

Archaeologically speaking, one of these stones was found in 2013 off Alderney in the wreck of a British 16^th century warship. This leads archaeologists to believe that there was some kind of association with navigation, why else would they be carrying one of these around on a warship, after all? However, Icelandic spar has never been found in any Norse excavations.

I became interested in the legend of the ‘sunstone’ during an exhibition I worked on during my Master’s degree. Our exhibition was about the art and science of light, and we decided to include three specimens of Icelandic Spar in our exhibition. If you are interested in reading more about the historical, archaeological, and museum related contexts please click here to be taken to the post on my blog Museum Malarkey.

Thanks for reading,

Jamie