Uridium

• Metallic element discovered by Humans by the 22nd century (ENT Novel: Beneath the Raptor's Wing)
• Stable as uridite ore or when alloyed with other metals, but unstable in raw form (DS9: "Civil Defense"; "Indiscretion")
  • Can explode on exposure to electrical charge (DS9: "Civil Defense")
• Uridium alloy common in starship construction (DS9: "Indiscretion")