Of all the jewels in Tolkien’s legend the most notorious are the silmarils, which seem to have the universal effect of being desired by everyone. These jewels contain the light of the two trees of Valinor which mesmerize those who look upon them. Feanor and his sons desired the jewels because Feanor made them, and the Valar desired them to revive the trees, but all the rest who look upon the silmarils have no excuse for their lust other than the fact that they are enchanted by them. This enchantment is so strong that it spawns almost all conflicts between the tribes of the elves and the elves and the dwarves in The Silmarillion, and even causes those who would be hurt by touching them to crave them nonetheless. This is made clear when Morgoth is scared by the jewels when he first takes them. Due to the fact that Morgoth had fallen from grace, when he laid hands on the silmarils he was burnt, yet he still craved them and never let them out of his sight. The jewels have the same damaging effect on all people or creatures that are dishonorable such as the sons Feanor or the beast Carcharoth when he swallowed the silmaril taken by Beren. Presumably, the silmarils would also have had the same effect on Ungoliant, when she demanded them from Morgoth, but she apparently undaunted by that prospect. The very light of the silmarils has the power to spark desire in the onlooker no matter what the results would be afterwards. However, this is not consistent for other objects that harbor the same light.
According to both The Silmarillion and The Tale of the Sun and the Moon, the sun and moon are also objects that originate from the two trees. The moon is a vessel containing a rose from Telperion, and the sun is a vessel containing a fruit from Laurelin. They are both vessels producing holly light, and are therefore also jewels. Though these two objects contain only a small portion of the light of trees and only the silmarils contain the light before it was poisoned by Ungoliant, the light still exists in them. Yet this light has the opposite effect on Morgoth or any other creature of evil than that of the silmarils. Rather than desiring the sun and the moon, Morgoth is repelled by their light for “Arien (the maiar who guides the sun) Morgoth feared with a great fear,” (The Silmarillion, chapter 11), and it is made clear in The Two Towers that none of orcs, save those specially bred by Saruman, can withstand the light of day. Perhaps all evil creatures would be repulsed by any light that comes from the trees and that the silmarils simply have the extra effect of creating uncontrollable desire, but the repulsive effect of the sun and moon is still witnessed from the light of the silmarils in other jewels.
In The Fellowship of the Ring, Galadriel gives Frodo a phial contain the light of the star of Earendil. Technically, the light from the star is still light from a silmaril, and it is this that makes this jewel very bizarre. First of all, this jewel has the same repulsive effect on evil that the sun and the moon have on evil creatures. This is demonstrated with Frodo’s and Sam’s encounter with Shelob, who hates and fears the light enough to leave Frodo and Sam alone (the opposite reaction of Ungoliant), and it repels the watching force of Cirith Ungol, which allows Sam to rescue Frodo. In this respect the phial seems far more powerful than the silmarils. However, the phial’s light then seems to fail Frodo in the chamber where the ring was forged. This is odd given that no craft of evil has ever daunted light from a silmaril and what is more, this craft is not of Morgoth’s design but of Sauron’s who is not even at full strength. Finally, a more curious effect of the jewel is that although Frodo is comforted by the object, he does not covet it in the same way anyone desires a silmaril, nor does Sam. In fact, there is no instance when a mortal man is ever seduced by the light of a silmaril. True, Beren is the only mortal ever to see a silmaril up close and he is unique, but the light did not seem to have the same effect on him as any elf. He gladly gave the silmaril to Thingol in order to wed Luthien, thinking her a better prize. Furthermore, though Beren was undoubtedly of purest heart as a man can be, the silmaril still burnt him because he was mortal. It is perhaps this fact that makes the effects of the jewels different for different people. It is not just that the power of the jewels affects individuals based on whether they are good or evil, but that mortals might perceive the jewels differently from immortals.
The silmarils are also hardly the only jewels that evoke different reaction from the races of Middle Earth. In The Silmarillion it is said that the elves love most the stars, whereas men love most the sun, yet both clearly produce the same light to both species. Additionally, in The Hobbit, the dwarves are fanatic about the arkenstone, whereas Bilbo gladly gives it up to preserve the peace, which makes it seem as though hobbits are not as affected by a desire for it. Yet, hobbits do seem to have an attraction to the palantiri as Pippin did in The Two Towers more so than anyone else of the company. It might be said then that Tolkien’s jewels have an effect on each race according the nature of that race. The silmarils are desired most by immortals because it reminds them most of their own nature. Likewise, men are attracted to objects that are useful like the palantiri and of course the ring, and dwarves are attracted to objects that represent wealth. This is perhaps why the rings of power were so tempting to each according to his race and why perhaps they might not be as attractive to the other races. Just as we had difficulty in understanding the significance of gems in class given the upbringing of our generation, each race might understand a jewel differently based on its respective nature, and therefore the power of the jewel is different for each race.