It is a variety of quartz. The color in yellow (citrine) or purple (amethyst) will depend on the temperature of crystallization.
Many of citrines marketed are obtained by heating of amethysts. The darkest color is said " citrine Madeira ". For these gemstones, the naming " topaz Madeira " was used. This name is now forbidden. it created a confusion (sometimes maintained) with Topazes, gemstones of higher commercial value. So, of numerous owners of citrines Madeira is persuaded to possess topazes.
During the Antiquity it was often cut in cabochon or used to realize intaglios, so creating amulets known as lucky charm and as protection against the evil eye.
For the Greeks, it symbolized the prosperity; it was used to worship Persephone and Demeter, goddesses of the spring and the harvest. So, this stone was called " stone of the traders ", because these thought that by keeping it in their pad of accounts, the money would stay there and would increase.
The citrine was used a lot in jewelry(jeweler's store) in the 1940s.
The majority of citrines result from Brazil and particularly from state of Rio Grande do Sul.
In ancient times, the citrine was used against snake bites.
To know more about Citrine, see Mindat.org->
