calcedony
/kælˈsɛdəni/
noun
- A type of quartz that is usually white, gray, or blue and has a waxy luster, often used in jewelry.
- She wore a necklace made of polished calcedony beads.
- The geologist identified the mineral as calcedony because of its smooth, waxy surface.
- Calcedony is often carved into cameos and other decorative objects.