Emerald is highly prized as a gemstone and by weight is the most valuable gemstone in the world

Emerald is a variety of the mineral beryl, colored green by trace amounts of chromium and sometimes vanadium.

Beryl has a hardness of 7.5 - 8 on the 10 point Mohs scale of hardness. However, the effective hardness of an emerald is often reduced by fractures and inclusions. Most emeralds are highly included, so the toughness (resistance to breakage) is classified as generally poor.

Emeralds come in many shades of green and bluish green. There is a wide spectrum of clarity, dependent on the inclusions and fractures in the crystal. Clear stones with dark yet vibrant color command the highest prices.

Emeralds in antiquity were mined by the Egyptians and in Austria, as well as Swat in northern Pakistan

Colombian emeralds are generally the most prized due to their transparency and fire. Some of the rarest emeralds come from three main areas in Colombia: Muzo, Coscuez, and Chivor. Fine emeralds are also found in other countries, such as Zambia, Brazil, Zimbabwe, Madagascar, Pakistan, India, Afghanistan and Russia.

The value of an emerald depends on cut, color, clarity, and carat.