sardonyx

plural sardonyxes

1. countableuncountableA gemstone having bands of red sard; a variety of onyx or chalcedony.

   The fifth, sardonyx; the sixth, sardius; the seventh, chrysolyte; the eighth, beryl; the ninth, a topaz; the tenth, a chrysoprasus; the eleventh, a jacinth; the twelfth, an amethyst.

   1611, The Holy Bible, […] (King James Version), London: […] Robert Barker, […], →OCLC, Revelation 21:20

   2 more examples

   The large chalice at right is carved from a single chunk of sardonyx, a kind of onyx. Its gilded rim and base are decorated with tiny enamels depicting a host of popular saints, including Nicephorus (farthest left on rim), a Ninth Century patriarch and opponent of a religious movement to destroy icons.

   1980, Colin Thubron, Seafarers: The Venetians, page 40

   I was wondering at these hanging gardens amid the forest of pink and white marble, red sardonyx, blue-gray, and cream, and black bricks, and green and yellow and tyrian tiles, when the sight of a lansquenet guarding the entrance to a casern reminded me of the promise I had made the officer of the peltasts the night before.

   1980, Gene Wolfe, chapter XVI, in The Shadow of the Torturer (The Book of the New Sun; 1), New York: Simon & Schuster, →ISBN, page 151