Gelignite

Gelignite was an explosive material which contained in it nitroglycerin. It could be detonated by gunshot or grenade. (TV: Pyramids of Mars, Battlefield)

Ernie Clements kept a store of gelignite which he used for fishing. It had started to "sweat", or exude nitroglycerin, making it extremely unstable. The Fourth Doctor used a box of this explosive to destroy the Osiran war missile being created by Sutekh's servitors. Sarah was able to detonate the box by shooting it with a rifle. (TV: Pyramids of Mars)

As a teenager, Ace had homemade gelignite—an early version of Nitro-9—which she told her art teacher, Mrs Parkinson, was a lump of school plasticine. Mrs Parkinson brought it back to the art room, Ace threw an armed grenade into the room, which landed and exploded "right in the middle of Class 1C's prize-winning pottery pig collection". (TV: Battlefield) She was ultimately suspended for blowing up the art room, in her words as a "creative act". (TV: Dragonfire)

Ace was attempting to extract nitroglycerin from gelignite when she was transported to Iceworld. (TV: Dragonfire)

Behind the scenes

In the real world, gelignite, unlike dynamite, doesn't sweat and can't be exploded without a detonator.