The short answer
Sardius stones in the Bible were probably a semi-precious stone called carnelian. But they point to a wonderful truth: that physical objects are never simply physical. All objects, especially precious stones, have a profound meaning and depth that is often missing in today's world.
As far as we can tell, a sardius stone (sometimes called “sard stone" or “sardine”) was an ancient name for carnelian, a reddish mineral used as a semi-precious stone. Use of the sardius for decoration goes back seemingly to 400 BC, and the stone is found all over the world: South America, Asia, Africa, and Europe. The stone has a rich history of associations with priests, kingship, healers, and general good luck. Like almost everything in nature, ancient people associated stones with various spiritual properties, effects on the mind and body, and important symbolism.
The sardius stone is frequently mentioned in the Bible with reference to royalty and riches:
Exodus 28:17 - "You shall set in it four rows of stones. A row of sardius, topaz, and carbuncle shall be the first row;" (ESV)
Exodus 39:10 - "And they set in it four rows of stones. A row of sardius, topaz, and carbuncle was the first row." (ESV)
Revelation 4:3 - "And he who sat there had the appearance of jasper and carnelian, and around the throne was a rainbow that had the appearance of an emerald." (ESV)
However, for most mainstream modern people, if you start talking about the spiritual properties of stones, their affect on your emotions, or “crystal energies”, you’ll probably get a few strange looks, since this sort of thing tends to get associated in contemporary thought with New Age spirituality and pseudo-science. But ancient people did not have the same sorts of tidy distinctions that modern people enjoy, not because they were less sophisticated than us, but because, in technical sense, they were more sophisticated.
The world as enchanted vs. disenchanted
The reason is that modern people tend to look at the world as –technically speaking – inherently meaningless. A tree is “just” an organism, a water is “just” liquid, and a stone is “just” a mineral. The assumption is that these things, inherently, have no real meaning to them. That doesn’t mean we can’t give them meaning, or use them as symbols to represent certain ideas, or that we can’t create personal attachments to them, but the basic way of thinking is that objects in nature don’t have any special meaning. Any meaning that they have is the meaning that they have to us, in other words, our subjective view of them. This is what the philosopher Charles Taylor called a “disenchanted” way of thinking about the world.
The opposite way of thinking is called an “enchanted” view of the world. On an enchanted view of reality, everything in the world has an inherent or intrinsic meaning, regardless of what someone thinks about it. On an enchanted way of thinking, trees might have particular meanings related to growth, age, wisdom, and fertility; water might have meanings related to purity, compassion, and life; and certain stones might have meaning because they’re associated with certain deities or spirits.
The exact meaning of these things is dependent on the assumptions a culture makes about the universe, especially the nature of their gods. If fire, for example, is a gift that was taught to mankind by the titan god Prometheus, then the deeper meaning of fire is that it is something both powerful and dangerous, it is related to invention and discovery, and – most importantly –there’s a divine element in discovery and invention. If you were an ancient Greek lighting a fire, you wouldn’t just be remembering the story of Prometheus, in the act of lighting a fire you’d become a participant in that story, the inheritor of a divine gift and a participant in one of the arts of the gods. In other words, you would have entered into that narrative, and narrative is what gives meaning to reality.
What narrative gave meaning to things like the sardius stone in the Bible? The Biblical accounts don’t normally give explanations for the meaning of certain elements –like gold or pearls or carnelia –so it’s hard to say specifically, but the various authors were writing under certain mythological assumptions that were common to ancient world, so it is possible to generalize a bit. Generally speaking, because all ancient cultures viewed the world in an enchanted way, they believed that all physical things had spiritual significance. Every metal, stone, and element was related in some way to one of the gods or planets. This is what made up the ancient sciences of alchemy and astrology –both were systems that organized the elements of the natural world and the heavens. For example, the metal tin was associated with Jupiter, and with his virtues, like wisdom. Iron was associated with Mars and connected with power, courage, stamina, and masculinity.
Sardius stones in the Bible
But, you might ask, didn’t the ancient Israelites –who wrote the Old Testament –not believe in any of that, since they didn’t believe in the pagan deities? Not exactly. It’s a common misconception that the ancient Israelites and early Christians disbelieved in the pagan deities. In reality, they believed in them but viewed them as fallen gods –beings who had once been entrusted to watch over and steward the Earth, but fell because of their disordered desires and were now in open rebellion to the rest of the cosmic order. This is why the Biblical texts refer to the God of Israel as the “God of gods”, “Lord of lords”, “Lord of hosts”, and “the most high”. In other words, other gods existed, but the God of Israel was the highest. And once we get to the New Testament era, Jesus reveals that he (and his Father and the Holy Spirit) is in fact so much higher than the other gods that he – unlike them –is uncreated, uncaused, and the source of being itself. You can read more about the ancient Christian understanding about the fall of the gods in our article on Tartak.
How then do we understand the references in the Bible to these various stones and their meanings? Again, it’s difficult to give an exact answer, but given that even the Biblical authors assumed some version of a complex, cosmic narrative involving the influence and action of various spiritual beings, it’s easy to see the references to sardius in the Bible as having spiritual associations along the same lines as the other cultures at the time. For example, the reason they adorned the high priest in Exodus with these stones, was, as the text says, “For glory and for beauty” (Exodus 28:2), because the stones themselves represent both the riches of the earth and the connection with the heavens. The collection of stones on the breastplate of the high priest featured not just sardius, but also topaz, carbuncle, turquoise, sapphire, diamond, jacinth, agate, amethyst, beryl, onyx, and jasper (Exodus 28:17-20; names of the stones vary by translation).
That there are twelve precious stones on a breastplate that is also inscribed with the names of the twelve tribes of Israel is no coincidence. And because we’re dealing with an ancient culture that thought in an enchanted way, I would guess that each of these stones had a specific spiritual meaning. Because the Biblical narrative doesn’t explain those meanings, we can assume that the original audience didn’t need it explained to them –that kind of symbolism would have been obvious in their culture, just as we use certain symbols in the modern world that we don’t explain because we assume everyone is familiar with them.
Therefore, we can only speculate about the exact meaning of those stones, and different resources will give different theories, but more important than settling on one exact meaning is understanding the way ancient people interacted with the physical world, namely, that everything had meaning. A stone was never just as stone.
