Exodus 28:9-10

28:9 “You are to take two onyx stones and engrave on them the names of the sons of Israel, ¹  28:10 six ²  of their names on one stone, and the six remaining names on the second stone, according to the order of their birth. ³ 

[28:9]  ¹ tn Although this is normally translated “Israelites,” here a more literal translation is clearer because it refers to the names of the twelve tribes – the actual sons of Israel.

[28:10]  ² tn This is in apposition to the direct object of the verb “engrave.” It further defines how the names were to be engraved – six on one and the other six on the other.

[28:10]  ³ tn Heb “according to their begettings” (the major word in the book of Genesis). What is meant is that the names would be listed in the order of their ages.