It is interesting to consider the line between crafting and natural existence of gemstones. They together straddle a very thin line regarding these two modes of existence which is reflected in Tolkien’s species on Middle Earth. Gems here represent pure essence of virtue and meaning, they contain light. We see in Marbode’s writings that the color of a gem and the light it emits is a signal of the inherent power it contains. Gems are most valuable when they are flawless, with perfect, uniform color that fluoresces brilliant colors. By existing in such a perfect form, they embrace the uniqueness of a power. They can be thought to contain within them the pure virtue.
Tolkien certainly believes so, to the point that the silmarils, the most beautiful gems ever created, are made by capturing the light of the gods (from the Two Trees of Valinor) and encapsulating it inside of an unbreakable, flawless shell. In their purity they contain the essence of something, they have an inherent brilliance that comes from the light inside. How, then, is a gem made?
Precious stones on our Earth are made deep underground, where intense pressure and heat turns certain elements into beautiful macroscopic crystals. In Middle Earth, it is not discussed but likely the stones were carried to Middle Earth from Valinor, where gems make up the land, as seen when Eärendil gets covered in diamond dust walking on the shore. Then, great mines are dug deep into the earth by dwarves or men (or someone searches in streams and rivers) and the ugly unpolished rocks are collected. Finally, a gemcutter, who has trained for many years will carefully polish the stone and carve it into shapes, either simple facets that are designed to maximise their reflection and beauty, or they may carve complex shapes, like horses, faces, or geometric shapes. These carvings are made to improve their magical and/or spiritual powers, or to be aesthetically pleasing. Gems are often then set in elaborate pieces of gold and silver jewelry, and the most famous jewels are even well known for being traded among various settings.
The exact elemental composition combined with the conditions of its creation give it very specific properties, and if done just right results in flawless stones of bright and unique colors. Their purity ensures that they are the essence of the power, the light, if you will. But no stone comes out of the Earth looking beautiful. The stones must be crafted by living hands. They must be shaped and formed and polished and set before being recognisable. Take for example the Arkenstone, the most valuable stone to Thorin son of Thrain, son of Thror, and his family, much of the reason he goes to take back the lonely mountain in the Hobbit. It was dug up from deep in the earth, and then dwarves shaped it from a rock into a beautiful gem.
We can now understand several aspects of the different beings in Tolkien’s works. The dwarves covet beautiful gemstones and dig deep into their mines to retrieve them. They have the most advanced craftsmen that make gold, silver, and mithril settings for the stones. And the dwarves collect hoards of stones, never having enough. But the dwarves are only the craftsmen, they are the miners and the shapers, they are not the creators. The stones they dig up are created by the Valar in Valinor and then were presumably carried to Middle Earth. Only long after their creation are the gems shaped in ways that enhance their light. We then have two distinct groups: the creator and the craftsmen.
And yet perhaps the most important stones Tolkien writes about are the silmarils, and they are made by a Noldor, Fëanor. He is the creator of the stones. But, the light of the silmarils is not made by the stone’s creator, but taken from the Trees of the Valar and immobilised in a solid object. So in this case, who is the craftsman? Who is the creator? It is Fëanor so far as it is his creation, and yet he cannot take ownership of something that contains a light that is not his (the light of the Two Trees). He is the architect of the stone, but not the creator of the virtue, which can only be attributed to the Valar. In that sense, he is similar to the dwarves, who are not the creators of the lights in the stones, but only know how to accentuate the beauty they contain and take possession of them. But Fëanor is more than that. He built the stones. He made the permanent and flawless enclosure, which is an important feat in itself. Without the gemstone, the light cannot be contained. Without the light, the rock is not a gem.
Fëanor must then form a third group, but who else should be included? As we continue through the first and second age, we eventually find Fëanor's grandson Celebrimbor creating the rings of power with a disguised Sauron after creating a brotherhood of jewelmakers, the Gwaith-i-Mírdain. The three elven rings, the most powerful outside of the One Ring and forged in secret, each contain a different gem. The stones' origins are not discussed, but they were presumably made by the elves, although while ‘made’ certainly means crafted and set, it is hard to say with any certainty where the Noldor found the light (read power) inside the stones.
Eventually, Sauron reveals himself and wages war on the elves, but the important part is we never again see a creator of gemstones. There are two known creators of gems outside of the Valar - Fëanor and Celebrimbor. Sauron might know how, but his one ring is simply a band, so it is likely that Celebrimbor used familial knowledge to forge the stones. Of course, if Sauron was teaching Celebrimbor to encapsulate power, then he must have knowledge of creating stones, but Sauron is not important here because he never creates a gem that we know of (his ring of power is just a gold band). I will therefore assume it is only the two Noldor that have created stones outside of the Valar.
These elves do not fit into the two categories. They are not solely craftsmen or architects of the jewelry. And yet, they are not the source of the light, either. The Noldor are in between, they can condense the essence of light and encapsulate it permanently. And by the Noldor I mean specifically Fëanor and Celebrimbor, as we never hear about other Gwaith-i-Mírdain and have no knowledge of other stones made by an elf. After Celebrimbor's death, the elves do not even covet gold and gems like men and dwarves, who never escape greed. The elves of middle earth do not pursue the power of stones and outside of their three elven rings of power, we hardly ever see them with notable gemstones. They are even able to restrict themselves from using the three elven rings while Sauron has his one ring, which prevents his takeover of their power.
What is Tolkien saying about the creator, then? Fëanor and Celebrimbor are in their own category, a step between gods and mortals, similar to many other characteristics of elves. Something which does not really exist on our Earth. They have a skill of creating and crafting. The elves can encapsulate power in a physical form, and then they can craft them into beautiful things. It is a skill not shared with any other race, and one that does not have a comparably skilled counterpart in our world. The elves are a unique brand as Children of Iluvatar that have no counterpart in our world.
-David J. Goldfeld