The varieties of crystal are divided according to their colors and the other features that they contain.
According to the colors, they can be divided into the following five categories:
(1) Crystal: Colorless and transparent crystal. In some countries, the crystal that is used as the gemstone often has the name of Diamond, such as Alaska Diamond, Arizona Diamond and so on.
(2) Amethyst: The purple and transparent crystalloid. It is of the مزید valuable members in the crystal family. It has been very مقبول with people for its beautiful purple and...
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