Star Wars: the Old Republic, Fragile Hope
Cortosis ore shorts out lightsaber blades on contact, forcing the wielder to reignite their weapon.
Cortosis-weave was a swordsmithing technique commonly used on high-quality vibroblades and other melee weapons when combat with opponents wielding lightsabers was considered to be likely. It also was a descriptor for equipment that had been crafted utilizing cortosis ore. Cortosis-weave was employed primarily because it made the weapon able to withstand lightsaber blows. They could also be fashioned into armor or other gear. Weapons needed very little cortosis to be effective but armor required a substantially larger amount. The greater quantity provided an additional benefit to wearers though—a lightsaber would deactivate after contact was made with cortosis armor. Cortosis was extremely rare though and, thus, extremely expensive, resulting in few weapons and armor made with it. Several cultures developed various techniques for insulating traditional melee weapons against such sparring damage, but the art of bonding cortosis to blades in such a manner was first perfected by Echani weaponsmiths sometime prior to the Mandalorian Wars.