Which stone in Exodus 28:17 is the sardius?

The sardius in the first row of the breastplate: it is the first, red stone, which in the Hebrew text is called “odem.” In the Synodal translation, it is rendered as “ruby”; however, the name “sardius” comes primarily from the ancient Greek translation tradition and does not necessarily mean modern mineralogical ruby.

The first stone of the first row

In the book of Exodus, the high priest Aaron is commanded to wear the breastplate of judgment with twelve precious stones representing the twelve tribes of Israel, and the first stone in the first row is named, which translations may render as carnelian, sardius, or ruby.

“You shall set in it settings of stones, four rows of stones: a row of sardius, topaz, and carbuncle shall be the first row;” Exodus 28:17

Therefore, if you read translations that say “ruby,” that corresponds directly to the sardius: it is the first stone of the first row, not the topaz and not the emerald or carbuncle.

The Hebrew word “odem” and the name “sardius”

In the original Hebrew text, the word אֹדֶם (*odem*) is used, which is related to the word for “red”; thus, the primary characteristic of this precious stone was its red or reddish-brown color. The ancient Greek translation of the Old Testament, the Septuagint, renders it with the word *sardion*, from which come the names “sardius,” “sard,” and partly “carnelian.” Because ancient stone names described primarily color, luster, place of origin, or outward appearance rather than modern chemical composition, it is impossible to equate the biblical *odem* to modern ruby with absolute certainty. Most likely, it was a prized red stone: perhaps carnelian, red chalcedony, sard, or another variety of stone that ancient translators associated with the sardius.

Why translations differ

The word “ruby” in older translations should not be automatically understood as the transparent red corundum that modern gemology defines as ruby. Translators often chose the name of a precious red stone familiar to their readers, whereas other translations sought to preserve the ancient name “sardius” or translate it as “carnelian.” Therefore, the concise answer is this: the sardius is the stone rendered as “ruby” in some traditional translations—namely, the first stone of the first row of the breastplate; more precisely, it can simply be designated as a red stone, “odem.” The breastplate itself was a reminder that the high priest represented God's people before the Lord, for on the stones were engraved the names of the sons of Israel.

The sardius in other biblical imagery

The name of the sardius stone also appears in the figurative description of glory and beauty bestowed by God in the prophecy concerning the king of Tyre.

“You were in Eden, the garden of God; every precious stone was your covering, sardius, topaz, and diamond, beryl, onyx, and jasper, sapphire, emerald, and carbuncle; and crafted in gold were your settings and your engravings.” Ezekiel 28:13

In the book of Revelation, the hue of the sardius is associated with the majestic vision of God’s throne.

“And he who sat there had the appearance of jasper and carnelian [sardius], and around the throne was a rainbow that had the appearance of an emerald.” Revelation 4:3

At the same time, one should avoid the common misconception that sardius is the first foundation stone of the New Jerusalem: in that list, it ranks sixth.

“the sixth, sardius; the seventh, chrysolite; the eighth, beryl; the ninth, topaz; the tenth, chrysoprase; the eleventh, jacinth; the twelfth, amethyst.” Revelation 21:20

Conclusion and practical application

Thus, in Exodus 28:17, the sardius corresponds to the very first stone—rendered as ruby in some translations—while the Hebrew *odem* is most reliably explained as a red precious stone without overly rigid ties to modern classifications. Practically, this teaches us to read biblical lists of stones attentively: comparing translations, taking the original languages into account, and avoiding building essential doctrines on uncertain mineralogical identifications. Instead, we are invited to see the heart of the passage: God deeply values His people and desires that our service to Him be holy, beautiful, and faithful.