Bdellium, which signifies either a precious gum, of which see Num_11:7, or gems and pearls. Once for all observe, that many of the Hebrew words or names of stones, trees, birds, and beasts, are even to the Hebrew doctors and others, both ancient and modern interpreters, of uncertain signification, and that without any considerable inconvenience to us, who are free from the obligations which the Jews were formerly under of procuring such stones, and abstaining in their diet from such beasts and birds as then were sufficiently known to them; and if any were doubtful, they had one safe course, to abstain from them.
The onyx stone, a kind of precious stone, of which see Exo_25:7, Exo_28:9, Exo_28:20.