Khaydarin crystal

"You must seize the Khaydarin Crystals. For within them lies power undreamed of by the Protoss. Go now, my Cerebrate. Secure the crystals, and bring swift wrath to all who oppose the Swarm!"

- The Overmind gives instructions during the zerg invasion of Aiur

Khaydarin crystals are psi-active, monolithic psionic artifacts left behind by the xel'naga on various worlds. They are composed of blue-hued organic stones. Their name means "focused of the heart" in the Khalani language. They are frequently associated with xel'naga temples (such as those at Bhekar Ro and Nemaka).

Khaydarin crystals feel cold when touched, causing an aching pain and a 'tingling feeling', at least to terrans. Protoss feel the tingling sensation but without pain, though these differing feelings may be based on the size of the crystal as opposed to differing physiology. The crystals themselves can also be affected by outside stimuli to an extent, such as the Khalis and Uraj crystals becoming altered by their users and their environment.

Khaydarin crystals also possess abilities amounting to levitation. This is demonstrated in pylons and even some landmasses on Aiur, with giant crystals floating in the sky, rock strata having formed around them.

Uses of the Crystals
Khaydarin crystals can perform multiple functions. The energies of the crystals can only be processed by creatures created by the xel'naga.

Xel'naga
The crystals were used by the xel'naga to facilitate their genetic experiments in an unknown manner. The xel'naga also used them as 'computers'; a particularly large crystal appeared to act like a xel'naga-designed artificial intelligence. The xel'naga could also use the crystals as "storehouses of information", playing such a role in the caverns beneath Aiur.

Protoss
The protoss use them to strengthen their psionic bond and power their psionic technology. Khaydarin crystals were used by Khas to restore the protoss psionic link at the heart of the Khala, leading to the end of the Aeon of Strife. They have been used by the protoss to enhance their psionic energies (several protoss unit energy upgrades use khaydarin components). They can also help protoss focus and calm their minds.

Similar to the xel'naga, the protoss have demonstrated the ability to use khaydarin crystals to store information, particuarly those situated on the moon of Ehlna-unique energies found there provided the means to do so. These crystals vary in terms of the amount of data they could hold, and became "worn" when used, requiring transfer of the memories to new crystals.

Some protoss aerospace craft use khaydarin crystals directly. Khaydarin crystals are part of the computer system of the warp prism and a huge khaydarin crystal infused with a vast amount of psionic energy is situated at heart of each mothership, providing it with energy.

Psionic Matrix

 * Main article: Psionic matrix

Protoss structures and, to a lesser extent, units, draw their energy from a great psionic energy matrix that emanates from Aiur. While a nexus provides a link to this matrix, khaydarin crystal-based pylons are needed to actually tap into the energy required to provide psionic energy to new colonies. Each pylon generates a short-ranged aura of energy, which can provide the power needed by structures and warp gates. If a protoss building loses its connection to the psionic matrix, it will shut down until it is reconnected, and new units cannot be gated in if there is insufficient psionic energy to provide them with power.

Khaydarin crystals are part of the computer system of the warp prism.

Control of Zerg
To a limited extent, terrans have been able to use khaydarin crystals to control zerg – the most famous example being Alan Schezar's control of zerg on Aiur, who used protoss technology and ghosts to do the deed.

Warped Crystals
The powerful dark archon Ulrezaj created a series of six "warped copies" of khaydarin crystals from Dark Templar and zerg energy. These crystals could be used to control zerg.

The crystals could lead protoss from one crystal to another, and they could only be destroyed by the psychic fury of a dark archon.

One crystal was used to control zerg forces on Korhal, supporting Schezar's Scavengers. Ulrezaj used the other five crystals to control a number of zerg on Char. He planned to use the crystals to create "genetically" enhanced zerg which would be immune to the effects of the xel'naga temple of Shakuras, then unleash these minions onto the planet. The Dark Templar would flee to their hiding places, leaving the Khalai out in the open where they would be slaughtered.

However, this plan was foiled. Upon discovering the crystals, Zeratul ordered an assault force, including a Dark Archon Hero, to destroy the crystals. Upon their destruction, the enslaved zerg became dormant.

Protoss Game Effects
High templars wear Khaydarin Amulets to enhance their wide variety of psionic abilities.

Arbiters possess Khaydarin Cores to enhance their wide variety of psionic abilities.

Pylons are khaydarin crystal-based psionic links to the psionic matrix on Aiur.

Shield batteries are khaydarin crystal-based psionic energy stores.

Warp prism computer cores contain khaydarin crystals.

Motherships possess a giant khaydarin crystal core to enhance their wide variety of psionic abilities.

Khaydarin crystals in general (including Uraj and Khalis) are power-ups, while the crystal formation is an invincible protoss special building (placed via StarEdit).

History
A fairly large amount of khaydarin was present on Aiur, homeland of the protoss, seemingly left behind by the xel'naga. The mystic Khas and his student Temlaa stumbled upon a group of them during their travels in the latter part of the Aeon of Strife and quickly discovered their ability to recreate the lost protoss psionic link.

Studying the crystals enabled the two to decipher numerous old xel'naga artifacts which they and the Shelak Tribe had guarded during the civil war. This led them to the Aiur caverns, an underground xel'naga city, and after using the crystals to gain entrance to the chambers, they found a giant khaydarin crystal in its heart. The crystal had been previously used to drain the lives of several protoss from different tribes, but Khas was determined to subject himself to the crystal's abilities. It started to drain him, after which Temlaa reversed the ability, causing it to heal Khas. When Khas awoke, he told Temlaa that the crystal had "shared" with him and taught him many things about the protoss psionic link and the xel'naga themselves.

The zerg Overmind were able to learn how to manipulate the energies of the crystals after absorbing many xel'naga.

Prior to the Great War, Tassadar's Expeditionary Force discovered a number of zerg probes near terran space. Unable to identify the organisms, they were at last subjected to the khaydarin crystals, which naturally reacted with the creatures, identifying them as creations of the xel'naga.

During the Fall of Aiur, the zerg were able to obtain small amounts of the crystals. The Overmind insisted that the protoss temple on the site where the xel'naga first set foot on Aiur be destroyed and the crystal placed onto the cleared site so it could manifest itself on Aiur.

In 2503, torrential rains on Helios uncovered alien ruins along with a khaydarin crystal buried among them. Two opposing terran factions engaged in battle over the artifact.

Known Khaydarin Crystals

 * Khaydarin crystal formation (The Invasion of Aiur)
 * Argus Stone
 * Giant Crystal
 * Khalis
 * Uraj