Gold

Category:Resources
Once highly prized on Earth due to its scarcity and aesthetics, today its non-reactivity is valued for impulse engines.
Used in: All engines (tiers I, II, and III), plus Lateral Thruster and Fighter Bay modules.
(spoilers!)
 
Common sources: Bonuses from surveying Anomalies, destroying enemy ships, purchases from Trade factions on the cheap (e.g. Wiskamug) or from those which use it as a reserve currency against something that faction values at a premium (e.g. Selling Etherine or Iridium to the CXTA, selling Uranium or Copper to the Nimion).
Remarks: Even the largest, fastest ship could not use more than approximately 2400 Gold in its engines (typical ships more like 1500). If you have maxed out your ship's propulsion according to the ship's bridge classification, consider selling excess Gold to the Aquarian Traders or using it as currency to buy select resources from the CXTA or Nimion to your advantage).