Last time I wrote a little about the concept of 'hardness' as applied to gems and minerals. The Lord of the Rings contains many passing references to the relative hardness of materials, but this hardness has a mythic quality in that it directly correlates with technological sophistication of the smiths associated with that substance. For example, the Ents easily destroy the country rock that forms the outbuildings and walls of Isengard, but they are unable to make a dent in Orthanc, a tower built by the long-vanished Númenorëans, who may have faced it with some kind of volcanic glass (cunningly reinforced with carbon fibre, I like to think.).

But when Wormtongue tosses the Palantír or Seeing Stone of Orthanc from an upstairs window, it makes a distinct chip in the Númenorëan step on which it falls -- a step against which the rage of Treebeard has had no effect at all. (This may be significant: in an early draft of the relevant passage in The Two Towers, Tolkien has the Stone shatter on impact, but he quickly changed his mind for obvious dramatic reasons. Another change of mind occurred in drafts for what became the Appendices to the The Lord of the Rings, where it says that the Palantír of Weathertop went down with King Arvedui in a ship wreck: earlier versions of the same passage say explicitly that the Stone was broken. The Palantíri, made by the Elves of the Ancient West, are to Orthanc what Orthanc is to regular building stone, and this is reflected in the durability of the materials whence they are made.

So what are Seeing Stones made of, then? Tolkien reports that they were gifts from the Elves to the Faithful of Númenor, having been made long before in Valinor by the Noldor, possibly even by Fëanor, the greatest craftsman who ever lived. Allow me, if you will, to take you on a guided tour of the long vanished laboratory of Fëanor. Given that Middle-Earth Rules need not apply to Valinor, what follows is even more fanciful than all that stuff about mithril I discussed last time. But please bear with me.

Tolkien writes that the Seeing Stones permit the sight of small images of things far away. As described, then, they are no more than telescopes, but given their properties as described in The Lord of the Rings they are more like 'hypertelescopes', able to image things not in a direct line of sight, or obscured by intervening matter, such as clouds or mountains. But the main purpose of seeing stones is to act as communicators. Leaving aside the psychical aspects of Seeing Stones as beyond the scope of this article, it is possible to imagine two Stones being in communication by a phenomenon called quantum entanglement.

Quantum entanglement is a process in which two particles (such as photons of light) are generated together in such a way that they are, in the quantum sense, aspects of the 'same' particle: being intimately entwined, they can potentially remain in communication with each other when the particles are far apart: so that if the quantum state of one of the particles is altered, this alteration will show up in the other particle, no matter where in the Universe it is. Nothing shows up the inherent weirdness of the quantum world so much as quantum entanglement -- what Einstein called 'spooky action at a distance' -- yet the phenomenon is already being explored in such fields as advanced computing and cryptography. If you were to make all the Seeing Stones at once so that they shared the same quantum 'state', they would still be able to communicate with one another despite being separated. A change in the environment of one of them -- such as the impression of the thoughts of a person in the vicinity -- will be communicated to the others, instantly.

How could this be done? The tale lies in the making. One of the most intriguing substances to come out of research into advanced materials is lithium niobate, a glassy substance with a blue-green cast that has all kinds of interesting optical properties. One of these is called 'parametric down-conversion': shine a single photon of light at a piece of lithium niobate, and two photons will emerge. These photons will have twice the wavelength of the original (that is, their colour will have shifted to the red end of the spectrum), but the key thing is that they will be entangled. Lithium niobate looks like a very promising ingredient for a Seeing Stone.

But there's more to seeing stones than communication in some abstract sense -- they must also be able to communicate images. Lithium niobate is promising here, too: if you shine a bright enough light on it, the electrons in the material can be persuaded to shuffle around, changing the optical properties of the material. If matters are arranged in just the right way, you can create a hologram: basically, an image can be made to appear inside the material, as if it were a crystal ball. Lithium niobate just gets better and better as an ingredient for a Seeing Stone.

Lithium niobate, for all its wonderful properties, is unlikely to be as hard as Seeing Stones so obviously were, so some other substance is required. Happily, I have just the thing, and it is called beta carbon nitride. This fabulous substance, it has to be said, is almost as mythical as the Seeing Stones themselves. Calculations suggest that it should be even harder than diamond -- that is, its hardness would go to 11. The trouble is that nobody has managed to synthesize it, although some scientists believe that they might have come very close. Alpha carbon nitride, on the other hand, is already known as a greyish substance, and stands to beta carbon nitride as the graphite in your pencil stands to diamond -- graphite and diamond both being forms of the same substance, in this case pure carbon.

I propose that Seeing Stones were made of thousands of alternating, microscopically thin layers of lithium niobate and beta carbon nitride. This structure would have preserved the hardness of the substance but would have allowed a little flexibility, so that a Seeing Stone would have bounced if casually lobbed from a high window -- rather than shattering into millions of pieces, as a diamond might. (For all that it is very hard, diamond is very brittle and can be smashed with a hammer. Don't try this at home, especially not with the jewellery of a loved one -- at least, not until you have checked the terms of their insurance and booked a cab out of town.) Such a layered construction would have given the Seeing Stones a pearl-like iridescence, caused by the interference of light with the alternating layers: real pearls from the ocean are iridescent precisely because they have this kind of structure, and this in turn suggests a wonderfully elvish mode for the manufacture of Seeing Stones. Rather than having been carved, forged or moulded, the Seeing Stones would have been grown, layer by layer, in the similar way to the growth of a pearl by the accumulation of layers of nacre. When Fëanor made the Seeing Stones, they were his characteristically Noldorin answer to the pearls that his Telerin cousins scattered across the beaches of Eldamar.

While Fëanor was creating the Stones, he might have put beta carbon nitride and lithium niobate to another use. Tolkien explicitly states that the substance of the Silmarils will never be known until the world is unmade: a proscription which I view, naturally, as a challenge. The Silmarils could have been made from alternating layers of lithium niobate and beta carbon nitride, or perhaps a core of lithium niobate surrounded by a hard shell of beta carbon nitride.

You will recall that Fëanor used the Silmarils to capture the immortal light of the Two Trees of Valinor; that they appeared to shine of their own radiance, and that they enriched and amplified any light that fell on them. Without wishing to speculate on the nature of the Two Trees themselves, their images could have been preserved holographically within the Silmarils, exploiting the properties of lithium niobate. But the Silmarils could also have exploited yet another property of lithium niobate, rather like parametric down-conversion, but in reverse. That property is called 'second-harmonic generation': this means that in certain rather contrived conditions the material halves the wavelength of light that is shone on it, shifting it towards the bluer end of the spectrum. In effect, this would allow a Silmaril to absorb non-visible radiation, such as heat, and re-transmit it as visible light, giving the impression that the Silmarils would shine of their own accord, as well as responding to ambient light by shining even more brightly.

I'd like to propose one rather more sinister property of Silmarils -- they were radioactive, having been doped with uranium or radium. Glass doped with tiny amounts of uranium glows with a characteristic blue radiance, but radioactivity could also explain another essential property of the Silmarils. That is, they had been hallowed by the Valar such that any unclean hand that touched them would be scorched. When Melkor stole the Silmarils from Fëanor's treasury at Formenos, his hands were burned in the act of theft, so that they were blackened and painful ever after: possibly the first known case of radiation burns.

Once again I'd like to thank Karl Ziemelis and Edmund Gerstner for their invaluable help in researching and writing this article.

-- Olog-hai