Were not these different stones to describe the different lustres and graces of the Holy Spirit given to believers? 1 Corinthians 12:4-11.
Exodus 39:8-14
8 And he made the breastplate of cunning work, like the work of the ephod; of gold, blue, and purple, and scarlet, and fine twined linen.
9 It was foursquare; they made the breastplate double: a span was the length thereof, and a span the breadth thereof, being doubled.
10 And they set in it four rows of stones: the first row was a sardius,a a topaz, and a carbuncle: this was the first row.
11 And the second row, an emerald, a sapphire, and a diamond.
12 And the third row, a ligure, an agate, and an amethyst.
13 And the fourth row, a beryl, an onyx, and a jasper: they were inclosed in ouches of gold in their inclosings.
14 And the stones were according to the names of the children of Israel, twelve, according to their names, like the engravings of a signet, every one with his name, according to the twelve tribes.