Chalcedony
/kælˈsɛd.ə.ni/
"Chalcedony" in a Sentence (2 examples)
My mother gave me a necklace made of beautiful blue chalcedony stones.
Although there are dozens of different types of gems, among the best known and most important are […] . (Common gem materials not addressed in this article include amber, amethyst, chalcedony, garnet, lazurite, malachite, opals, peridot, rhodonite, spinel, tourmaline, turquoise and zircon.)