Naquadah

The Naquadah or Naqahdah is a superheavy metal, within the fictional universe of Stargate SG-1 (as well as in the film, where it is not named, but is mentioned as a similar material to quartz although it is not clear why. Some fans speculate that this similarity comes from its piezoelectric properties). It has a gray luster in its natural form and is bright green in its liquid state. Regarding the name of this mineral, the variant "naquahdah" It seems to be the most used, even on official sites for the series.

Naqahdah is the cornerstone of all Goa'uld technology, and is the material used to handle the large amounts of energy required to create a stable wormhole through the Stargate which is almost entirely composed of Naqahdah..

This mineral also has explosive properties, making it useful for improving bombs and missiles. There are at least four variants: solid Naqahdah, liquid Naqahdah (used in the staff weapons of Jaffa warriors), heavy liquid Naqahdah (mentioned in a dream sequence in the series), and the Naquadriah (unstable isotope). The Goa'uld also have other mining operations on several planets, extracting the ore to refine it into Naqahdah for military use, which is even rarer than pure Naquadah.

The Naqahdah is very rare, and does not exist naturally in our solar system. Some of the naqadah used on Earth comes from P3X-403, where, as a result of negotiations made by Daniel Jackson with the native Unas there, the Unas work the mines and deliver the naqahdah to Stargate Command. The Unas agreed to this in order to prevent humans from desecrating their sacred sites, and to cooperate in the war against the Goa'uld, also enemies of the Unas.

The Naqahdah is also part of the Goa'uld genome. Their presence gives them the ability to use their technology, and to sense the presence of other Goa'uld within a short distance. The host of a Goa'uld symbiote has Naqahdah in their blood, and the metal remains in their systems even when the symbiote has been removed. The only exception to this are the artificially cloned symbiotes and the Goa'uld who remained on their homeworld (P3X-888) where it was found that there was no naqahdah. It is believed that the high use of Naqahdah-based technology may have introduced the metal into their systems after abandoning P3X-888.

The Naqahdah allows the creation of Naqahdah Reactors and class 2 Naqahdah Reactors, which are a lesser source of power than the ZPM, but very useful in hyperdrives, weapons and to activate 7 chevrons in the Stargate, which which allows creating wormholes within the same galaxy.

The Naqahdah is apparently the most common exchange commodity in the area where the Goa'uld have dominated; Lucian Alliance merchants prefer the more refined Naquadah.