Harmonic Voidcrystal Activation

Strange, ancient crystals that consume light, rather than refract it can be used to

Utility

Basic The crystals are able to create planar disturbances when they vibrate. A roughly cut crystal can be used as a weapon or tool by mounting it and striking it - the vibrations are very destructive to all matter and can also interfere with energy flow.
Targeted When crafted just right and vibrated at a specific frequency, the crystals can slice long lasting gateways to other planes, or create shortcuts across planes.
Enhanced When vibrated by a complex and harmonised song, they can be used to craft objects not out of wood or stone, but out of the very stuff of planes. These techniques were used to construct the warding stones that (long after their original creation) became the anchors for the great barrier.
The throat-singing songs of the Goliaths were originally composed to link with specially crafted and magically enchanted void crystals. The Goliaths place great value in their tradition of passing the songs perfectly from one generation to the next. This tradition was intentionally cultivated in them by those who understood the application of the songs.

Impact

As the capabilities of the crystals were discovered there were some who sought to use them as weapons and some who sought to use them for defense. Many protective wards were created, as well as weapons with various effects. Diligent research and experimentation provided effects capable of combating the very primordials that brought the crystals into existence.

Access & Availability

At the present time there are almost no living creatures who know of voidcrystal or know of any deposits or stores of it. There are certainly none living who know what can be achieved by harmonically activating it. There is documentation relating this information, though it is arcane, cryptic and esoteric. Only a few of the most determined researchers and cultists are anywhere close to unearthing and understanding such things.

Discovery

The voidcrystals themselves were created in ancient times when the primordials coalesced. Where these beings entered the planes, they caused the appearance of dark crystals carrying some essence of the void from which they came. Sometimes these were found and their properties discovered. Sometimes the primordials destroyed all sentient life in the vicinity and the voidcrystals that marked their arrival on that plane still rest where they first appeared. Initial usage was basic, but more advanced uses were discovered over time. Higher levels of control of the vibrational activation of the crystals lead to more and more powerful effects.