John Gill Commentary Exodus 28:13

"And thou shalt make settings of gold," — Exodus 28:13 (ASV)

And you shall make sockets of gold .
] Or sockets of gold, to put the two onyx stones in, (Exodus 28:11) for of other ouches we read not, except the enclosings, in which the twelve stones of the breastplate were set, (Exodus 28:20) and these are again mentioned because of the chains to be fastened to them, of which in the following verse.