Main Menu Site

Classic doublespar crystals from Helgustadir on a recent stamp

Source : Icelandic Post

Click below :
Calcite - Calcit - Calcite - Calcita

Europe : Iceland : Giant doublespar (Calcite) crystals up to 7 m length at Helgustadir farm site

Coordinates : 65°02'N , 13°50'W : Helgustadir, Outer Reydarfjördur, central eastern Iceland

Helgustadir is the name of a farmsite on the northern shore of the Reydarfjord in the outer east of Iceland. This deposit of outstanding transparent calcite was discovered in the 17th century and was intermittently mined for many decades until 1924. The transparency of the crystals where sufficient for the optical industry and therefore the calcite quickly became famous as "Iceland spar" and its marvelous crystals were rapidly distributed among the leading european scientists of that time. The initial concepts of double refraction and crystal cleavage planes were first discovered on calcite crystals from this site and led to a far better understanding of crystal physics.

The calcite crystals, which are accompanied by small tufts of stilbite crystals reach a size of several meters. RÖSLER (1981 : Lehrbuch der Mineralogie) quotes a maximum size of 6 x 2 m , but dont give any more details. Other authors describe 7 x 7 x 2 m large crystals. A crystal of 230 kg is said to be on display in the exhibition of the Museum of Natural History in London (yet unconfirmed).

Today there remain large dumps of the former mining activity, whereas the mine as such is most of the year filled with snow and more or less inacessible. It is still possible to find small cleavage pieces of double spar calcite on the dumps, especially after periods of rain, which is not a rarity in Iceland. However collecting is forbidden by law, as Helgustadir was declared a national heritage site in 1975.

Update October 2006 : Courtesy of L. Kristjansson a detailed publication about the Helgustadir Iceland Spar locality is now available in the Library section.

Update January 2007 : An explanation table was added to the site recently, as can be seen at, which also has some more images on the Helgustadir locality.


Helgustadir in a nutshell :

Mineralogy :

Calcite with minor zeolites

Crystal Size :

7 x 7 x 2 m confirmed

Geology & Origin :

Hydrothermal crevice filling in basaltic rock of tertiary age,possibly partly pneumatolytic

Status :

Often inaccessible due to snow conditions, dumps of former mining activity

Remarks :

A famous place of eminent importance to the history of natural sciences (see under "Resources")


Other notable & famous calcite occurences :

Note : Calcite is one of the most common minerals world wide, therefore large and even giant calcite crystals are considered not to be very rare. Hence there are certainly other remarkable giant calcite occurences not listed here.

- More information about giant Iceland spar occurences can be found here (New Mexiko, USA), here (Hejiawan, China), and here (Garibaldi mine, Australia)

- Another remarkable Iceland spar deposit with crystals up to 0,7 x 0,5 cm occur in basalt from Nizhnyaya, Krasnoyarsk kray Siberia, GUS.

- Sharp yellow scalenohedral crystals up to 1 m occur with galena and sphalerite in the famous Tri State District, Oklahoma / Missouri / Kansas, USA.

- For more information about calcite pseudomorphs after giant ikaite crystals and crystal aggregates please look here and here.

- Large to giant crystals of calcite up to 1 x 1 m size from metamorphic marbles have been reported from Sterlingbush, New York, USA.

- Large dendritic ferruginous calcite crystals up to 2 m site are deposited by epithermal springs in Sisak Cermik, Turkey.


Snow filled Helgustadir mine site in April

Photo : Mr. L. Kristjansson


Inside the old quarry on a rainy day.
Note the white remains of the calcite vein

Photo : Mr. L. Kristjansson


Slightly weathered calcite crystals from the Helgustadir mine

Photo : Flaviano, on



Resources and relevant weblinks :

For more information on the mineral calcite please look at, Webmineral and the german Mineralienatlas.

Strange enough, scientific interest in the Helgustadir site ceased almost completely in the 20th century. The most modern literature survey about the Helgustadir site and its influence on the scientific community was recently compiled by icelandic Dr. Leo Kristjansson who works at the Geophysics Department of Iceland university. It can be found here.

Please have also a look at his website, where you can find his extensive literature survey about Helgustadir




Have you been at the site ? Do you know more details
or have discovered any errors ?
Please contact us !