A. color, transparency
Generally speaking, amethyst and topaz are the most valuable varieties of crystals.The two are further graded according to the depth of their colors, with the darker grade A and the lighter grade B.The price with general darker color is tall, but want to be a standard with not deep dark.There are two colors: the color of the crystal itself and the color of the internal inclusions.The color of crystal itself wants gorgeous, sterling, distribution wants even, cannot too deep or too shallow, be like Australian jade, blue chalcedony, amethyst, topaz, its price is high.Colorless crystals contain inclusions of bright color, its price is also high, such as titanium crystal, green ghost, red rabbit hair.
Crystal - crystalline minerals
Amethyst generally with a little cloud, dark purple color, crystal transparent for the top grade.
According to the transparency index, the more transparent the crystal, the higher the price, good transparent crystal processing of the finished product crystal clear, brilliant dazzling.The crystal with high diaphaneity can promote the gorgeous color, otherwise appear inflexible without intelligence.Optical crystal requires full transparency, no double crystal, no impurity.Process crystal requires transparency, less crack, less defects.Melting crystal requires transparency, may have more cracks.The value of the three successively reduced, melting crystal can only be used as the raw material of melting crystal glass.In craft crystal, the crystal is bigger, can use crystal glasses and carve high-grade handicraft, price is higher accordingly