Emerald is the most precious member of the Beryl family. It exhibits a distinct and recognizable pure green hue but can also be found in a bluish-green hue. On Mohs¡¯ scale of hardness, emerald is 7.5-8. It has a vitreous luster and sources include Colombia, Zimbabwe, South Africa, Russia (Urals), Afghanistan, Australia (New South Wales, Western Australia), Ghana, India, Madagascar, Malawi, Mozambique, Namibia, Nigeria, Pakistan, Zambia, Tanzania, and the United States (North Carolina).

The beauty of Colombian emeralds, known for their extraordinary color and crystallization, is unique since their formation process occurred in a different geological environment than all the other known emerald deposits. They are found in black argillaceous limestone of the Upper Cretaceous age, which was deposited in a sea separating North and South America.

During the Continental drift, the Andes Mountains were formed, and beds that were originally at the bottom of the sea found themselves at the top of the mountains. While folding, the rocks fractured, which provided space for the growth of calcite veins. Hot magma followed by hot gases and fluids permeated through the cracks, bringing with them the elements necessary to crystallize emeralds. These gases were trapped in the crust of the fold in the eastern cordillera of the Andes by an impermeable shale formation. Since calcite veins are porous and permeable, the emeralds had an opportunity to crystallize while the gasses and fluids cooled off.

Color

 

Emerald exhibits an incomparable pure green hue but can also be found in a bluish-green hue.