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.
Garnets are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. All species of garnets possess similar physical properties and crystal forms, but differ in chemical composition. Garnet species are found in many colors including red, orange, yellow, green, purple, brown, blue, black, pink, and colorless, with reddish shades most common. The mineral group shows a range of hardness on the Mohs scale of about 6.5-7.5.