The answer is: An onyx

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

In the book of Exodus, when we think of the splendid high priest’s attire, it’s hard not to be captivated by the details—the vibrant colors, the intricate designs, and, of course, the stones. The twelve names of the tribes of Israel didn’t just receive a casual engraving; they were artistically crafted into majestic stones—specifically onyx—for the priest’s ephod, a ceremonial garment worn by Aaron. This symbolism goes deep; it's as if each tribe was personally represented before the Divine, honoring their unique role within the larger narrative of the Israelites.

The onyx stones were not just mundane pieces; they held beauty, rarity, and significance, echoing a steadfast connection to the land and the people they represented. Fun fact—the onyx used in Ancient Israel is a gemstone renowned for its rich color variations, often signifying strength and protection. In some cultures, it was also believed to have healing properties.

Moreover, wearing the names of each tribe was akin to carrying their weight and burdens into sacred space, highlighting a shared spiritual journey. This gesture reinforced that, while they were distinct, they were ultimately part of one community longing for connection with the divine.

Throughout the scriptures, stones often bear witness to faith, from the stone tablets of the Ten Commandments to the "living stones" that believers are described as in the New Testament. Each story interweaves, reminding readers of the continuous thread of spiritual identity and purpose.