Kyber crystals were Force-attuned crystals that grew rarely but throughout the galaxy, with some areas having a greater abundance than others. The crystals concentrated energy in a unique manner through the Force, resonating with it. The crystals exhibited a sort of "collective consciousness," verging on sentience, and could non-verbally communicate with both one another and living beings. Some theorized that the permutations in the kyber lattice were comparable to emotional shifts in a sentient being.
 
Internally, kyber crystals were composed of both organic and inorganic matter. They were stable at temperatures and pressures found in the cores of large stars, and were thus impervious to fire and resistant to hammering, and noted for their intricate patterns. Kyber crystals were sturdy enough to survive the violent explosion of a lightsaber's power grid, such as those caused by accidentally inverting the emitter matrix during the weapon's assembly.
 
Kyber crystals would not warm a sheath or a towel or any inanimate object, responding only to life, including plant life. If an individual were to wrap their hand around a crystal, the crystal would warm, but not change in temperature. The crystals grew in an organized way, adding to their prismatic structure one piece at a time. They had no discernible lifespan, and thus could be found from sizes as small as a fingernail to gigantic proportions. All kybers were attuned to the Force regardless of their size. Incorrectly pumping laser energy into the crystals weakened their lattices in the same way living cells were affected by radiation.