Huon

Active huon energy (DW: The Runaway Bride)

Huon particles were a type of particles that were destroyed in the Dark Times of the universe.

Huon particles were originally destroyed by the Time Lords near the end of the war with the Racnoss due to their being harmful. The Racnoss used them in their technology, to power their spacecraft and wake the hibernating young Racnoss at the core of the Earth. The only known remaining concentrations of Huon particles were small amounts in the heart of the Doctor's TARDIS. They were recreated using equipment at the Torchwood Institute.

It is unknown if the Torchwood Institute was working on creating Huon particles before the Empress of the Racnoss took over the base.

Huon particles could be created by using a hydrogen base to create them in liquid form. These inert liquid Huon particles needed to be activated in a living being, such as a human. The Huon particles could be drunk in water and would then be activated by stressful situations. This process would take as much as six months or as little as a few minutes, depending on the amount consumed and how quickly it was consumed. Once activated, the Huon particles would start to glow and become magnetised, attracting other Huon particles. If enough were absorbed (a whole gallon) it could even pull other Huon particles from different time zones (such as the Tardis). (DW: The Runaway Bride)

Jack Harkness speculated that Racnoss huon particles may have resulted in the Blessing, but was forced to admit he had no idea. (TW: The Blood Line)