What is another word for Iceland Spar?
Pronunciation: [ˈa͡ɪslənd spˈɑː] (IPA) 
Iceland Spar is a transparent mineral that belongs to the Calcite family. This mineral is renowned for its double refraction properties, which means it splits a light beam into two. Iceland Spar is also known as Optical Calcite, or the Viking Sunstone. Optical Calcite is sometimes used in optical devices such as microscopes, polarizers, and prisms. Viking Sunstone is an ancient term that refers to the use of Iceland Spar as a navigational tool in ancient Viking seafaring. It is believed that the Vikings used the double refraction property of the Iceland Spar to locate the position of the sun, particularly on cloudy days when the sun was not visible.
