Stargate - Alpha One

Naquadah is a mineral which is not found on Earth, which is used to power most of the technology used by the Goa’uld. It is a safer source of energy than nuclear power, and more durable than titanium.

Long ago, the Goa’uld altered their own genetic make-up so that they could gain more benefit from the device called the Sarcophagus, and somewhere along the way they did something which infused trace amounts of Naquadah into their bloodstream. Because of this, they are somehow able to detect the presence of the element in their environment or in other creatures.

This strange link they have with Naquadah not only lets them detect other symbiotes and former hosts, but they can also act as a power source for many of their devices.

See also: Naquadah Naquadriah