Resisting the lightsaber
Aside from the blade of another lightsaber, there were rare materials or creatures found throughout the galaxy that could withstand a lightsaber blade, but with varying degrees of success:
Cortosis, though a rare and expensive metal, became a common defense against lightsabers in the eras of the Sith Wars. One of the reasons that it was so expensive was the need to refine it. Pure, unrefined, freshly mined Cortosis ore was for unexplained reasons ionized, and anyone who touched it would be killed instantly. Near the end of the Clone Wars, the Separatist Droid Army employed cortosis battle droids in an attack on the Jedi Temple. Shortly after Order 66 was given, the Jedi Shadday Potkin attacked Darth Vader with a Cortosis blade during a failed ambush attempt on Kessel. There were three known methods of forging cortosis armor and weapons, each with varying effects:
The first method was to make the armor or weapon with a cortosis weave, which utilized the ore's primary elements. When contacted by a lightsaber's blade, the cortosis fibers that were worked into the metal caused a surge that shorted out the energy blade. The lightsaber could be reactivated immediately, but it gave the opponent the momentary upper hand. It can be assumed that the natural ionic properties of the material allow the cortosis fibers to penetrate the electromagnetic field created by the lightsaber arc before being sublimed into plasma. The presence of this solid within the blade arc creates the short. The drawback to the weave was that its alloy construction was still susceptible to damage from the lightsaber attack.
The most common (and inexpensive) method employed during the Jedi Civil War era was the use of a variant cortosis alloy that resisted the lightsaber blade itself, though it did not cause the lightsaber to deactivate as its more pure form did. This enabled troops to fight enemy Jedi or Sith blade to blade.
The rarest type of cortosis came in the form of a refined metal with all the impure elements removed. Thus purified, there were no "weaker" metals for the lightsaber to damage, and unique conducting elements remained to short out the energy blade. This refined alloy, nicknamed a cortosis shield was most often employed as armor.
Lightfoil were small and elegant energy swords based upon lightsaber design. They were popular among certain nobles of the Tapani sector, especially those that called themselves "saber rakes". Lightfoils were weaker than authentic lightsabers due to the poor quality focusing crystals used in their manufacture and the relatively low level of craftsmanship compared to Jedi artisans. On the plus side, though, they apparently did not require any connection to the Force to create, and were fully usable by non-Force sensitives.
Phrik, like cortosis, was a rare metal that could withstand the potency of a lightsaber blade, although unlike the aforementioned metal, Phrik did not possess the ability to cause the blade to short out. Phrik was most notably used in the construction of the electrostaffs wielded by General Grievous's MagnaGuards. Other notable uses of Phrik included elements of Palpatine's lightsaber and Dark Trooper armor.
Darkswords were an ancient type of sword which could be used to parry lightsaber blows, being made from a special material. Unlike cortosis, this material did not possess the ability to temporarily deactivate a lightsaber blade it made contact with.
A Jedi uses his lightsaber against a Vaklu soldier's cortosis alloy vibrosword.
A Jedi uses his lightsaber against a Vaklu soldier's cortosis alloy vibrosword.
Armorweave was a cloth said to give some resistance to lightsabers, though the protection the reinforced material afforded was limited.
Sith Alchemy was employed during the eras of the first Sith Empire to augment the properties of the applied metals so as to counter the seemingly unstoppable lightsaber. The Sith also made use of such elements as cortosis in the forging of their swords. After the original Sith Empire, the most notorious use of Sith alchemy was in the construction and reinforcement of Darth Vader's armor.
Mandalorian iron: A metal used by the Mandalorian warriors.
Yuuzhan Vong bio-engineered weaponry and armor, such as the amphistaff and Vonduun crab armor held a natural, limited resistance to the lightsaber; however, weaknesses were soon found in the armor and staff. Luke Skywalker's first engagement with this bio-technology ended favorably only after striking the Yuuzhan Vong spy's amphistaff repeatedly in the same spot, weakening and ultimately killing it.
Force Weapon: Similarly, weapons that had been imbued with the Force could be used to parry a lightsaber's blade without harm.
Water: All lightsabers, unless specially made,[14] would short out when they were (to some extent and period of time) submerged in water, due to rapid chain reactions and the instant overpowering of water on the blade. In rain, a lightsaber would steam up, but not short out.[7][23][5] See also Underwater Lightsaber.
Orbalisks: These parasitic and sometimes symbiotic creatures from Dxun had shells so strong even lightsaber blades could not penetrate it. When a Force user wore these creatures as a protective coat, it rendered the wearer virtually immune to most forms of attack. Darth Bane covered his entire body in orbalisks, excluding only his face, feet and hands thanks to special armor he crafted to stunt their growth.
Other counteracting materials existed in the galaxy, such as an unidentified super-conducting metal that was used for ship armor centuries before the Galactic Empire, as well as various energy shields, like Durge's. Some creatures, such as lava dragons, were possessed of natural armor that reflected the blade much as the blade reflected a blaster bolt. It is also probable that quantum-crystalline armor could not be cut by a lightsaber, as it was believed the only way to destroy the material was to send it into a black hole.