The Vikings

Iceland spar (crystal)

isl.kristal wiki

Source: http://en.wikipedia.org/wiki/Sunstone_(medieval)#mediaviewer/File:Silfurberg.jpg

Iceland spar is a transparent birefringent calcite or also Icelandic limestone (crystallized calcium carbonate). (Note: crystal generally will be described in other post…). It became well-known because of the Vikings who used it as “sun-stone”, capable to determine… Continue reading