Up for sale is this lovely Optical Calcite Rhombohedron which is also known as an Icelandic Spar. Calcite naturally cleaves into the rhombohedron shape.
The double-refraction property of this crystal was important to understanding the nature of light as a wave, which was studied by the likes of Isaac Newton and Christiaan Huygens.
This piece measures : 3.0” x 2.4x 1.6” (75mm x 61mm x 40mm)
Weight: 520g
This piece was mined out of Nueva Leon, Mexico.20-0012
