Also see definition of "Sardius" in Bible Study Dictionaries
Word Study
Sardius
CIDE DICTIONARY
Sardius, n. [L. sardius, lapis sardinus, Gr. , , . See Sard.].
A precious stone, probably a carnelian, one of which was set in Aaron's breastplate. Ex. xxviii. 17. [1913 Webster]
OXFORD DICTIONARY
Sardius, n. Bibl. etc. a precious stone.
Etymology
ME f. LL f. Gk sardios sard
Also see definition of "Sardius" in Bible Study Dictionaries
For further exploring for "Sardius" in Webster Dictionary Online