“Kylo Ren's lightsaber was a crossguard lightsaber constructed and utilized by Kylo Ren... was crudely assembled based on an ancient design dating back thousands of years… A single cracked Kyber crystal, barely able to contain the weapon's power, necessitated the lateral vents which diverted the extra heat produced by the crystal to either side of the hilt, and gave the weapon's red plasma blades an unstable, serrated appearance.” -http://starwars.wikia.com/wiki/Kylo_Ren's_lightsaber
Kylo Ren’s Kyber Crystal
Metal: Polished and Sandblasted Silver
Colors: 4 – ALL translucent
Backstamp: KYLO + MYFE.
“Kyber crystals were rare, Force-attuned crystals that grew in nature and were found on scattered planets across the galaxy. They were used by the Jedi and the Sith in the construction of their lightsabers. As part of Jedi training, younglings were sent to the Crystal Caves of the ice planet of Ilum to harvest crystals and then construct their own lightsabers. There were also larger, rarer crystals of great power and that, according to legends, were used at the heart of ancient superweapons by the Sith.”