While not itself a warp crystal, this bright purple Chaos Shard does have a connection with the chaotic psychic energies of the Far Realm (even to the point where it animated a golem made of such crystals). The Shard should probably be destroyed, but for the cost of 100 gp in materials, it can be forged into an implement with the following properties:
Warp Shard Implement
This glowing lump of blue crystal can be fitted to a rod, staff, or wand, allowing its user to channel the power of the Far Realm to smite enemies.
Critical: +1d6 psychic damage
Property: When you use this implement to attack with an arcane power with the psychic keyword, you can gain a +1 item bonus to damage rolls on that attack. When you gain the damage bonus, you also gain vulnerable 5 psychic damage until the start of your next turn. If you are a warlock with the star pact or a sorcerer with the Wild Magic class feature, you do not gain the vulnerable psychic.
Power (Daily ✦ Psychic): Free Action: Use this power when you hit with an arcane power with the psychic keyword. The power deals an additional 1d10 psychic damage.
When the meteor fell from the heavens, it shed many small fragments, or Chaos Shards, scattering them across the land and the Chaos Scar itself. The largest portion of the meteor ripped the great furrow in the earth that is now called the Chaos Scar. One of the Chaos Shards landed not far from the mouth of the Chaos Scar, where the King’s Wall now stands. There, it began to burrow into the earth, carving a twisting pattern of tunnels deep into the ground. At the bottom of a maddening, spiraling network of caverns and passageways, the shard slowly began to increase in power.
Shortly after coming to rest at the bottom of the network of tunnels the energy of the Chaos Shard caused clusters of crystals to grow throughout its domain. Called warp crystals by the races of the Underdark, these strange luminous crystals grow in areas with a strong connection to the Far Realm. The strange properties of warp crystal strengthen creatures from the Far Realm while weakening those native to other planes of existence.
The Chaos Shard exudes a malevolent aura of evil and chaos, and although it is not truly sentient, it does possess a crude, malignant will that draws other evil creatures to it. Recently, the combined influences of the Chaos Shard and the warp crystals have weakened the barriers between the world and the Far Realm, allowing a small group of fell taints, drawn by the power of the Chaos Shard, to pass into the mortal realm. The dim-witted fell taints, believing the Chaos Shard to be a god, took to worshiping it and sought to please it by offering up mortal sacrifices. The fell taints had been venturing out and attacking travelers near the King’s Wall, and their victims were carried back to the spiral and either devoured or presented to the Chaos Shard as gruesome gifts.