Lexical Definition

‎σαρδόνυξ‎ sardónyx (sar-don'-oox) sardonyx ^G:N-M
from the base of ‎σάρδιος‎ and (the nail of a finger

sardonyx.

• hence the "onyx" stone)
• a "sardonyx", i.e. the gem so called

Abbott-Smith

* σαρδόνυξ (L, σαρδιόνυξ), -υχος, ὁ (< σάρδιον, ὄνυξ),
sardonyx, a stone marked by the red of the sard and the white of the onyx: Re 21:20.†

Abbott-Smith References

Liddell-Scott-Jones

σαρδόνυξ, ῠχος, ὁ,

(σάρδιον) sardonyx, [NT+4th c.BC+]The stone was called ὄνυξ when the dark ground was simply spotted or streaked with white, but σαρδόνυξ if the different colours were disposed in layers.

_{LSJ Scripture Refs: Rev.21.20}