Naquadah bomb

From The Stargate Omnipedia

Explosive device that utilizes naquadah as the source for the destructive yield. Many variations of this device exist. The earliest to modern human knowledge was used by the Supreme System Lord Ra when he intended to send a nuclear weapon back to Earth as a message. He had enhanced the explosive with a sample of naquadah. The device eventually detonated in orbit of Abydos.

Baal has performed similar handiwork on Earth. After settling in he constructed at least one building, the Halcyon Tower, where he had naquadah laced into its very infrastructure. He placed a detonator somewhere in the building, but this could not be located in a forty-five minute time period that he gave before detonation. The building would have destroyed a radius of at least five miles in downtown Seattle, but thanks to the Prometheus and its Asgard beams, the entire tower was transported into deep space, where it exploded.

See also: Goa'uld bomb

KEY EPISODES

"Stargate" the Movie - Ra, intent on sending a message to stay out of his affairs, plans to send a makeshift naquadah bomb through the Stargate to Earth, but instead it is used in his destruction.
Ex Deus Machina - Baal detonates a building he has built with deposits of naquadah as an insurance policy to prevent future attempts to capture him.