Quaestor Verus wrote:"...my research led to fruitful ends. I sought after every text that great library had to offer on the matter. And I concluded this: that the lightsaber is unique to every individual, in every component. This is the truth of the matter, and pragmatically how it must be; according to the history of the Jedi, lightsabers were seldom lent to others and never kept, as the unique factors contributing to the construction of the saber meant that it could only be efficiently used by its own creator.

How does this relate to the focusing crystal? Indeed, as you will see, it is integral. The focusing crystal is the heart of the lightsaber; it is chosen by the constructor of the saber itself, and often has profound implications. Exemplary historical lightsaber crystals include that of Jedi Master Mace Windu, whose crystal appeared to him via visions and to which end he sought it, and that of Jedi Master Revan, who used a Krayt Dragon pearl, and that of Darth Maul, who used synthetic creations that were not natural at all, but flawless by design. This brings up the natural question, what can be a lightsaber crystal?

Upon further research of more obscure examples, the true answer is that there is no effective limit to what might be introduced to the lightsaber. It seems the only limitations are the requirements that a.) it have the capacity to allow light to pass through it, and b.) that it be tuned to the specific lightsaber in which it is to be used, and c.) that only the individual constructing the lightsaber may tune the crystal.

How is a lightsaber crystal 'tuned'? Unfortunately, the ancient texts regarding this matter are hopelessly vague, and only those who have been instructed to completion among the Jedi are instructed regarding this matter. However, I have gone to some lengths and discovered this...that the tuning of a lightsaber crystal not only involves its focus to refract and resonate light to the correct specifications, but that also it needs to be imbued with the Force itself.

It is this last point that adds to the unique nature of each saber. But more importantly, it provides practice in meditation with the Force for the creator of the saber, and ensures that the saber is connected to its creator. For this reason, it was said that the saber was representative of the wielder's life itself, and that care should be taken not to lose it. How to imbue the crystal with the Force? Even I cannot say. It is this point that must be discovered by the individual creating the saber, and cannot be taught..."