Meteor

A meteor is a large clump of rock or other matter that is of extraterrestrial origin. They are known to sometimes crash onto the Earth's surface, which, depending on the site of impact, can cause significant damage to the infrastructure of local population centers. After striking the surface of the Earth, meteors create a large dent on the surface known as a crater.

Appearance
It is difficult to know what meteors look like before they land on the Earth's surface, as they almost always become damaged in the process. Meteors are known to come in multiple sizes, ranging from very small to quite large. They also come in different shapes, although are typically spherical. Before crashing on the Earth's surface, meteors catch fire due to the friction and heat that is created when they pass through the atmosphere with great velocity. In 100 ASC, when Team Avatar saw a meteor fly above them near Shu Jing, they saw that it was enveloped in blue flames and left a long trail of fire and smoke behind it. Shortly afterwards, it crashed near the town, where it left behind a crater and started a wildfire. Some parts of the meteorite (a new name given to a meteor after it lands on the Earth's surface) were still intact, but had been charred black due to the fire. The surviving rock was rough, hard, and heavy.

Meteor shower
Occasionally, a large group of burning meteors fly past or crash onto the Earth in sync, creating a natural yet dazzling light show known as a meteor shower. This name was chosen because they look somewhat like raindrops falling through the sky. The meteors burn blue as they pass through the Earth's atmosphere. According to Sokka, meteor showers make humanity feel small and insignificant.

Uses
There are a few known uses of the rock that meteors are made of. The blade of Sokka's sword was made of meteor rock, which, according to his master Piandao, made his sword a fine and formidable weapon. The color of the blade was black. Meteor rock is also used in jewelry, albeit only sporadically. Sokka once gave Toph a bendable bracelet made of meteor rock. It too was black.