Word Summary
sardion: sard, a sardian (stone)
Original Word: σάρδιον
Transliteration: sardion
Phonetic Spelling: (sar'-dee-os)
Part of Speech: Noun, Neuter
Short Definition: sard, a sardian (stone)
Meaning: sard, a sardian (stone)
Strong's Concordance

Properly, an adjective from an uncertain base; sardian (lithos being implied), i.e. (as noun) the gem so called -- sardius.

Thayer's Greek Lexicon
STRONGS NT 4556: σάρδιον

σάρδιον, σαρδίου, τό (neuter of σάρδιος, see below), sard, sardius, a precious stone, of which there are two kinds, concerning which Theophrastus, de lapid. 16, 5, § 30, Schneid. edition says, τοῦ γάρ σαρδίου τό μέν διαφανες ἐρυθροτερον δέ καλεῖται θῆλυ, τό δέ διαφανες μέν μελαντερον δέ καίi ἄρσεν, the former of which is called carnelian (because flesh-colored; Hebrew אֹדֶם, the Sept. σάρδιον, Exodus 28:17; Exodus 36:17 (Exodus 39:10); Ezekiel 28:13; ἁιματοεντα σαρδια, the Orphica, de lapid. 16, 5), the latter sard: Revelation 4:3 (Rec. σαρδίνῳ); Revelation 21:20 G L T Tr WH. Hence, the adjective σάρδιος, σαρδια, σάρδιον (from Σάρδεις, cf. Pliny, h. n. 37, 7) sardine namely, λίθος (the full phrase occurs Exodus 35:8 (variant)): Revelation 21:20 Rec. (B. D., see under the words, Sardine, Sardius.)