Selfsame Stones

To the Wild Elves of the Great Forests, it is believed that plants hold memories, that trees can remember all actions performed to them and every word whispered into the wind. But to the beauty-craving Ink Elves, it is stone that has the longest memory. From lava to rock, rubble to gravel, stone remembers its former shapes and all forms of beauty that it has held. Granite and marble allow for great statues and reliefs to be carved, but for the artist bearing no tools, it is slate that allows the first, crude lines, these lines soon giving way to shape and form. Ink Elves believe that slate will never forget what was drawn upon it. And in some cases, they were right.
Selfsame Stones are, quite simply, stones that are twinned. Actions performed to one happen to the other, regardless of the distance between the pair. This makes them exceptional for communication across long distances. There are many challenges involved in using them in this way, however. The creation of Selfsame Stones is a precise and challenging ritual, meaning that most Stones created are very small. Instead of writing upon them as one would vellum, they are imprinted upon using emotional magic, leaving an aura on one Stone that both then share. This aura lasts until it is read from either Stone by an aura reader, normally at a Listening Outpost. By utilising the fact that a pair of Selfsame stones are identical, no matter the distance between them, one can commit a message through aura on the twin that resides at Ley-Lhoris that can then be read from the other at Caleb's Rest.
The creation of Selfsame Stones isn't a hidden secret, but it does take a dedicated artisan knowledgable in sculpting and magecraft, and so is often a profession that only the most talented Ink Elves take up, though there are tradesfolk of other ancestries who have studied the method. The key to creating a pair of Selfsame Stones is that, during creation, everything done to one must be done to the other simultaneously, down to the minutest details. A slip of the miner's chisel, a mis-carved detail, and even a mismatch in the mental conceptualisation between the sculptors can lead to the Stones not pairing. A set of Selfsame Stones must be identical, from beginning to end. This means that both stones must be extracted from the same vein of rock at the same time, maintaining an identical size and removal method. Then, they must be linked. The Ink Elves do this through art, carving intricate designs onto the two Stones, though it has been theorised that there are other ways of linking a pair. After the long process of extraction and sculpting, the pair are tested to see if they have correctly linked. Often, a pair will not, and thus serve no purpose past decoration.
The more frequent use of magic in Ley-Lhyandir has somewhat streamlined the Selfsame Stone creation process, though not enough to make it an easy affair. A sculptor with enough magical understanding can carve both Stones simultaneously through careful magical manipulation, ensuring that there will only be one design in mind throughout the process and that any mistakes happen to both, keeping the consistency regardless of happenstance.

Utility

Selfsame Stones are used for communications across the Planet and the Belt at Listening Outposts, such as the The Messenger Tower in Caleb's Rest. These Stones have allowed for fast communication for many years, and let those who drift apart stay in touch, though in some cases the price can prove prohibitive.

Manufacturing

The first step to creating a pair of Selfsame Stones is to identify a good vein of rock to begin working with. Most tend to choose something easy to sculpt with such as limestone or granite, though there have been successful Selfsame Stone pairs made from marble and even more exotic materials. Once the vein has been selected by the tradesman, they will begin the excavation process. The important thing to remember about the creation of Selfsame Stones is that anything done to one Stone must be done to the other. This means that the pair must be excavated in the same way, with the same position and pressure of the strikes of the chisel, ensuring that neither comes out with any difference. This tends to be the hardest part, as getting two chunks of stone to come away identically is a skill only the greatest mason will be capable of. 
Next, before a sculptor can begin carving into the Stones, they must conceptualise the design. With magical education being more widespread now, it's become easier to sculpt Selfsame Stones, as a practised mage can carve the Stones simultaneously, meaning only one person is needed for this step, but before magic was used, this step was much harder. Two sculptors would be needed, both being perfectly familiar with the intended design and, more importantly, both having the same intention in their minds. The mechanism that links the Stones is not yet fully understood, but study indicates that it is in part the act of treating the two Stones as one that allows them to link, and so even intent can influence whether or not the two Stones become a pair.
Finally, the Stones must be carved. Each pair has its own, unique design. Some are carved with simple animal imagery, or landscapes involving the Great Forest and flowing rivers, but more intricate ones can feature intricate sculpting of myths and legends or images of great people. In some cases, there are Stones inlaid with gold or gems, though these are few and far between due to the extra layers of complication behind their creation.

Access & Availability

Due to the difficulty behind the excavation, binding ritual and carving, Selfsame Stones aren't available for personal ownership or use. However, Listening Outposts in Ley-Lhoris and Ley-Lhyandir and across Layman's Belt have been created over the years, giving the average person the option to pay to send a message to any other major city. There are a small number of Selfsame Stones owned by the Matron, though it is unknown as to who the twins have been given to.

Complexity

Whilst the Selfsame Stones themselves are not complicated, the ritual process to create them is. Having to have everything be identical from start to finish leads to most Selfsame Stones being abandoned due to error or failure to keep consistency. This complexity has led to the Stones being worth a huge amount, and those who aim to learn the process spend much of their life dedicated to the craft before they make a single one.