CaCO3- Calcite (Calcium Carbonate)
Hexagonal crystalline structure divided into rhomboidal shape, most likely Iceland Spar
Structure
With a translucent and shimmering sheen, Calcite looks like a slanting and rainbow-flecked piece of glass, but has qualities of a prism with light refraction. These attributes come from the very structure of the stone's molecules, and are seen with the naked eye.
Calcite forms in many different textures and forms, colors and sizes, depending on the surroundings in which it was formed. Some of the largest crystals can be found in Iceland, and when cut into certain rhomboid forms, allows the stone to display it's anisotropic light-reflecting (bringing out other brilliant colors and refracting light in different directions, at different speeds).
Light and Polarity
The calcite has a quality of birefringence that divides light according to wavelength, so that it splits the spectrum of light into two. This creates polarized light, light that has a limited band of wavelength, and this birefringment is the same attribute given to sunglasses so that certain ultraviolet light bands can be diverted. These stones helped early scientists understand the wave-like qualities that light has.
The transparent and intriguing Iceland Spar has made photographing Calcite very rewarding, with its intricate and luminous light shows, and bizarre refractive structures.
