The emerald is part of a group of minerals called beryl. Its green color and intensity depend on traces and inclusions of chromium, vanadium and sometimes iron. It is part of the quartet of gems considered as precious along with ruby, sapphire and diamond.

Its rarity is due to the fact that exceptional geological conditions are required for its formation to occur: beryl is found in the magma of Earth's crust while chromium, vanadium and iron that make it emeralds are usually found in Earth's mantle. The rarity and price of an emerald depend on what is called the 4 C's: color, clarity, cut and carat; same as for diamonds.

"Emerald" comes from Latin "smaragdus", which is in turn a deformation of the Persian word "zamarat" which means "heart of stone".

About 3,500 years ago (according to some sources up to 5,000 years ago), the Egyptians mined it to make jewelry for royalty and aristocracy. The main ore deposit, which is called Djebel Zabarah, was also called "Cleopatra's mines" due to the fascination that the gem exerted on the famous Egyptian queen. The Greeks and Romans saw it as the stone of love and knowledge. For this reason, this gem was often associated with the goddesses Venus and Vesta (the goddess of home and family).

The mines of Colombia were already exploited by pre-Columbian civilizations. They used emeralds for decoration, as an offering to the gods and as currency. The Aztecs for their part called this gem "Quetzalitzli", making direct reference to its color and that of the Quetzal bird. According to Arthurian legends, the Holy Grail would have been made of emerald.

The emerald is recommended to those who seek balance and create better conditions for their travels or their daily lives. This gem relieves affective problems and harmonizes loving feelings. By stimulating memory, knowledge and wisdom, it encourages group cooperation while promoting tolerance and moderation. It also contributes to the resolution of old conflicts.

On the physical plane, the emerald is considered a regeneration gem that boosts vitality. It is beneficial for those who suffer from eye problems ranging from tiredness to cataracts. Since ancient times it is believed that it can prevent both the symptoms and seizures of epilepsy. The emerald is also reputed to ease childbirth if placed near a woman giving birth.

The emerald has a detoxifying effect on the liver, pancreas and kidneys, strengthening the immune system, the digestive system and the cardiovascular system. For these reasons it has been called the "stone of eternal youth".

Around the world, some 62 emerald deposits were registered in 19 countries. Colombia alone represents 60% of the world production of emeralds thanks to the Chivor, Muzo, Peñas Blancas and Cozcues mines. In addition to being the largest producer of this gem, Colombia is also where the highest quality emeralds come from. In some Colombian mines only, there is the Trapiche emerald variety, which is six-pointed star-shaped because the crystal forms in various directions. Its name is due to its resemblance to the main pinion of the sugar mill gears, which is used to extract the juice from the sugar cane.

Other producing countries are Zambia, Brazil, Russia, Zimbabwe and Madagascar. Some of the most famous emeralds are those of the National Bank of Bogotá, the ones from the Topkapi Palace in Istanbul, Turkey or the emerald of the Vienna Museum in Austria called "Moctezuma" since it was offered by the Aztec sovereign to Spanish conquistador Hernán Cortés.