iolites

/ˈaɪəlaɪts/
noun
  1. Plural of iolite; multiple pieces or types of the blue or violet gemstone.
    • She sorted through a tray of iolites, looking for the one with the deepest blue color.
    • The museum displayed a collection of iolites from different mines around the world.
    • Geologists study iolites to understand the metamorphic conditions under which they formed.