Calcite from Gard (Ref.300)

Calcite from the Gard department in France (old collection).

Chemical formula of calcite: CaCO₃ composed of calcium carbonate. Hardness: 3 on the Mohs scale. Density 2.6 to 2.8.

Stone dimensions: L: 60mm x W: 45mm x H : 68mm x weight with base: 223g.

The stone is presensed on acrylic base.

Calcite history: from the Vikings to the Middle Ages.

The Vikings used calcite, in particular a variety called 'Icelandic spar', as a 'sunstone' for navigation. This translucent, birefringent stone enabled navigators to locate the position of the sun even on cloudy or foggy days, thanks to its ability to polarise light. By looking through Icelandic spar, they could see a double image of the sun and thus determine its position.

Also in the Middle Ages, calcite was sometimes used in the windows of cathedrals and churches in the form of Iceland spar to create mystical lighting effects. The light passing through the calcite created halos and halos, adding to the sacred and spiritual atmosphere of places of worship.