In the 1940s, the crown was sold to, then broken up by, an American syndicate. Many of its stones are probably in the jewelry collections of wealthy Americans today. Emeralds vary in color from light to deep green. The stone can, however, lose its color when heated strongly. Beryl, or beryllium aluminum silicate in chemical jargon, is a six-sided symmetrical crystal.
Beryl contains beryllium, aluminum, silicon and oxygen.
But growing synthetic stones of fine quality began in the United States in 1946. There are also excellent imitation emeralds on the market made of colored cut glass. Emerald-bearing shale has undergone recrystallization due to changes in the physical environment such as pressure and temperature. Colombia produces the largest and highest quality emeralds. They were also discovered, and subsequently mined, in the Ural Mountains of Russia around 1830.