Menachite Forerunner crystal

The Forerunner Crystal was a Forerunner artifact that was discovered in an underground facility on Reach by Dr. Halsey and the surviving Spartan members of Red Team in 2552. The artifact is of incredible potential, capable of warping space, energy, and even time. It is hardly understood by the UNSC forces who found it, but is a prize that the Covenant were extremely eager to obtain.

Effect
When it enters Slipspace, the Crystal begins emitting radiation that causes a ship to move hundreds of times faster than it would during normal Slipspace travel. The realm that it opens is not normal Slipspace, because weapons' fire is allowed, which is not possible in regular Slipspace. Energy weapons will be horribly misdirected and will pop in and out of existence seemingly randomly, causing them to be as dangerous to the firer as the target.

Description
The Crystal is a fist-sized Forerunner artifact. When originally seen by Dr. Halsey and the SPARTANs in the underground facility on Reach, it was floating upright and the area around it was distorted by gravity. The crystal reacted with a burst of neutronic radiation at Halsey's touch. When exposed to a Covenant gravity beam, the crystal nullified it, reshaping itself in the process.

Appearance
When the Ascendant Justice jumped into Slipspace, the crystal again rearranged itself, emitting radiation during the entire jump, and caused gravitational distortions. The location of the ship at the end of this jump was somewhere near the Eridanus System, a distance that, from Reach, should have taken several days to traverse instead of a few minutes. By comparing timestamps from several missions Dr. Halsey discovered a three-week average time difference. Her conclusion was that the Crystal bent both space and time, so that it could be removed from Reach by Cortana and the Master Chief. Halsey later gave the crystal to Corporal Locklear, who covered it with C-7 Foaming Explosive and blew it up to avoid another Slipspace radiation spike, accidentally killing himself in the process.

Three shards of the crystal were recovered by the Covenant, which were presented to the Prophet of Truth by Tartarus in an orb-shaped container. Truth then ordered the Brute to reward the pilots that had recovered the shards, then kill them. The UNSC also possesses pieces of the crystal. It is unknown what has happened to the shards that were posessed by the two factions, although the three Covenant-recovered shards were likely lost when High Charity fell to the Flood invasion, or were kept aboard the Dreadnaught with Truth.

The rift that was projected when the ship went into slipspace may be similar to the Portal found at Earth. It is probable that the Forerunners used this crystal, or others like it, to travel throughout the galaxy and past its edge almost instantaneously.

Trivia

 * At the end of the novel Halo: First Strike, Truth is given a handful of the crystals. He then says it may be enough to complete what they need. It is possible that the Portal on Earth will not open unless some piece of the crystal is present, as a final key to safeguard the location of the Ark from the Flood.