Other than the more generic and generally used gemstones including from diamonds, rubies, sapphires, and emeralds, pearls and opal[24] have also been defined as precious within the jewellery trade. Up for the discoveries of bulk amethyst in Brazil inside the 19th century, amethyst was considered a "precious stone" as well, https://originalgemstones03680.jaiblogs.com/53690504/5-tips-about-gemstones-colors-and-names-you-can-use-today