Amethyst Genuine Gems suppiler Ring- 925 Silver Purple Amethyst Ring – Amethyst Ring, 925 Silver, Purple, good jewelry, Gemstone ring, black Friday gift, stacking rings, best item, Ring good jewelry, Amethyst Genuine Gems, Ring gift for anniversary day **** However, the most beautiful of all crystal quartzes also posed one or two riddles for the scientists, and indeed they still haven’t been completely solved to this day. The amethyst has its hardness (7), its moderate refraction and its weight in common with the other quartzes, but the crystal structure is different, and it is most unconventional. The construction is stratified, as a result of which areas and lamellae of varying colour intensity often come about. This explains why there are relatively few large cut amethysts of an evenly distributed dark colour, in spite of its having been found so abundantly in all parts of the world. It is only in the last few years that scientists have been fairly certain of having found the real ca use of the colour. It is now attributed to certain iron constituents in connection with natural radioactive radiation.