What rocks are similar to amethyst?

Amethyst is a purple variety of quartz, so other quartz varieties such as citrine (yellow quartz), smoky quartz, and rose quartz (pink quartz) are similar in composition. Additionally, minerals like fluorite can exhibit similar purple hues, and some varieties of purple sapphire and spinel may also resemble amethyst in color. However, these minerals differ in their chemical composition and crystal structure.