Optics calcite or iceland spar

ETYMOLOGY: The name comes from the latin word calx meaning lime.

CRYSTAL SYSTEM: Trigonal, hexagonal.


MINERAL CLASS: Carbonates.


Hardness: 3 on the Mohs scale.

FIEDS: Iceland, Mexico.


MINEROLOGY: Another common variety is called Iceland spar, which are fragments of completely colorless and transparent calcite. It was described in Iceland basalt cavities and have a high birefringence resulting in duplication of any image that we observe through the glass.

MYTHOLOGY: It was discovered in 1669 by Erasmus Bartholinus (Danish, 1625-1698) and Christian Huygens (Dutch, 1629-1695) discovered the polarization of the optical calcite. Each of the two emerging beams refraction of Iceland spar can be extinguished by passing it through a second crystal of the same material rotated about an axis in the same direction as the light beam. Thomas Pynchon (Novelist, Long Island, New York, May 8, 1937) makes the Iceland spar one of the central themes of his novel "Lit" published in 2006.
The Vikings (North Atlantic dominated for three centuries from 900 AD) tracked the sky with a glass of Iceland spar (natural polarizer on the optical property of splitting a beam of light), rotating it while sweeping the horizon in a circle . At some point it was significantly increased brightness through the glass. They determined and a line pointing to the sun. They continued sailing and repeated the operation. These two lines give a good estimate of where the star was. With a mobile device, they placed a torch in a position that direction simulating the star. With a sundial would find out not only the time but kept the position of the sun. Thus they determined and kept on track.


PROPERTIES: The wide images and the eye heals, it helps to see the double meaning hidden behind the words are said.



ZODIAC SIGN: Taurus, Cancer, Scorpio.

USES: Used for manufacturing precision optical instruments like petrographic polarizing allowing white light microscopes. Meditation, collection.

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