Dark Gem

Dark Gems are dark purple stones that appear in Spyro: A Hero's Tail. They have small bolts of pink electricity spurting from them. When planted, a Dark Gem destroys the surrounding environment and causes spiky vines to grow in their place. It also makes the surrounding area dark. The Dark Gems are the source of Red's evil. There are smaller pieces of Dark Gems known as Dark Shards, which release gems when destroyed.

History
At the start of the game, a Gnorc plants a Dark Gem into the ground, causing the surrounding nature to die off. Gnasty Gnorc and the other Gnorcs are carrying Dark Gems that they have been mining. A portal opens, and they jump through it with the Dark Gems to plant them into the Dragon Realms. The Professor saw what happened on his computer screen, and explains the situation to Spyro. He also tells Spyro that Dark Gems are the power source for Red, so in order to stop Red, Spyro has to destroy every Dark Gem. After their short discussion, Spyro begins his journey.

Early in his journey, Spyro was taught by Tomas how to use the Horn Dive maneuver, which gives him the ability to destroy the Dark Gems. There are a total of forty Dark Gems, and Spyro must destroy at least ten in each homeworld to destroy their dark gem force field so that he can access the boss area.