Milky CZ is another form of cubic zirconia, altered to make its form look milky. It comes in various colors, and can be cut into any shape.
Amethyst is a type of quartz that is mostly found in geodes and hollow agates. It is composed of silicon dioxide, and scores a 7 on the Mohs hardness scale. From different angles, amethyst occurs in primary hues from a light pinkish violet to a deep purple.