Onyx used in the Breastplate
Source: Nav
Exodus 28:9–12, 20
Take two onyx stones and engrave on them the names of the sons of Israel: / six of their names on one stone and the remaining six on the other, in the order of their birth. / Engrave the names of the sons of Israel on the two stones the way a gem cutter engraves a seal. Then mount the stones in gold filigree settings.
Exodus 39:6, 13
They mounted the onyx stones in gold filigree settings, engraved like a seal with the names of the sons of Israel. / and the fourth row had a beryl, an onyx, and a jasper. These stones were mounted in gold filigree settings.