Spire crystals

From Guild of Archivists

These glowing crystals, one of Spire's only natural resources, have unusual properties. It seems that something about their inner matrix allows them to collect an abundance of negative electric charges. Once it touches a grounded object, however, it loses its energy, making the crystal stop glowing, give an electric shock to whoever touches it, and produces sound very much like music. When it is grounded, electricity can pass straight through a crystal without affecting its inner matrix.

Sirrus had many uses for these crystals. By fixing them to floating rocks, to the roof of the garden, and to the dock, he created electromagnetic conductors, which he used to balance the flight of his Rock ship to the Nearest palace. He also took advantage of their "singing" properties and made an organ-like Spider Throne. However, he also used these crystals to create bombs, capable of destroying even the hardest nara walls.