"Jedi Sentinel is one of two Advanced Classes for the Jedi Knight, the other being the Jedi Guardian. Before the Jedi Purge, there were three Jedi Classes, one of which was the Jedi Sentinel along with the Jedi Guardian and Consular. The Sentinel is the counterpart of the Sith Marauder of the Sith Empire.
The Jedi Sentinel deals damage primarily through lightsaber strikes, though it does possess several Force powers, most noticeably the iconic Jedi Knight Force leap.” - http://swtor.wikia.com/wiki/Jedi_Sentinel
“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.” - http://starwars.wikia.com/wiki/Kyber_crystal
Jedi Sentinel Kyber Crystal
Metal: Polished Silver
Colors: 4 ALL Translucent
Backstamp: JEDI SENTINEL + MYFE.