The answer is: An onyx

Exo 28:9 - to be part of the priestly ephod

The stone you’re referring to, the onyx, played a remarkable role in the priestly garments of the Israelites. This wasn’t simply a choice of stone; it symbolized beauty and reverence in the relationship between God and the people. The high priest wore the ephod and had the names of the twelve tribes of Israel—each representing a unique lineage and history—symbolically carried on his shoulders, reminding him (and everyone else) of his responsibility for Israel’s spiritual welfare.

Now, let’s dig a little deeper into this gem. Onyx, known for its layered or banded style, reflects the idea of unity amidst diversity—no two colors or patterns alike, yet coming together in harmony. Could there be a neat parallel drawn about diversity within the tribes themselves? Each tribe contributed its identity and purpose to the larger story of Israel, akin to how these stones, distinct yet combined, create a breathtaking piece of art.

As you explore Exodus further, notice where other jewels pop up, especially in the construction of the tabernacle and the high priest’s garments. Gold, sapphire, and other precious stones get shout-outs along with onyx and stand as a testament to the beauty of divine favor. Interestingly, the name "Onyx" translates to “fingernail” in Greek, perhaps a gentle nod to God’s creation, demonstrating the intricacy of life—from the stones beneath our feet to the heroics of a collective family moving towards freedom. Isn’t beautiful symbolism just the best?