Sokka's sword

Description
When training with Piandao, Sokka made his own sword using ore from a meteorite. The material used gave the sword a distinctive black color. The sword is also able to cut through strong metals with little effort.

Sokka's sword is a Jian (Chinese straight sword). It is now part of his standard armament, along with his boomerang and club. In later episodes, he has affectionately named it "Space Sword".

The bottom of the hilt contains the symbol of the Order of the White Lotus.

During the arrival of Sozin's Comet, Sokka lost his sword while using it to dispatch a Fire Nation soldier on one of the airships. It is unknown if he found it.

Real Life Connections
Swords forged from meteorite iron have a long history, both in the real world and in fiction. It is believed that meteorite iron was the first iron ore used by civilization, before the development of mining to retrieve terrestrial iron. King Tut was entombed with a meteorite-iron dagger on his breast.

Meteorite iron swords are mentioned by Tolkien as having mystical powers and being able to cleave through normal blades. In the Redwall series by Brian Jacques, Martin the Warrior's broken sword is re-forged by Boar the Fighter using meteorite ore. In David Eddings' Belgariad novels, the Sword of The Rivan King was made from meteorite ore that the God Belar brought down to the earth.

There are a number of examples of meteorite blades in anime as well; perhaps the most well-known of these is Zantetsu-ken, the sword of Ishikawa Goemon XIII in the Lupin III animé, which is also known to be able to cut through almost any ordinary object. The Filipino comic book character Panday also has a meteorite-metal sword.

Additionally, in Phillip Pullman's His Dark Materials, the ice-bears forge their armor from iron from meteorites. The properties of meteorite ore make iron stronger than most metals, allowing the ice bears' armor to be nearly indestructible. Túrin Turanbar, from Silmarillion, uses a dark-iron sword forged from a meteorite

Trivia
Sokka's sword and sheath, as well as Piandao's sword and sheath, are designed based upon real swords owned by Sifu Kisu. Kisu is the martial arts consultant for the show's creators, and he was the reference for Piandao.