Author's Note: Just what was Plato talking about when he mentioned orichalicum in context with Atlantis? The stuff has been used in fiction for, oh, I don't know how long, in fiction and in computer games like Indiana Jones and the Fate of Atlantis. I suspect that Disney's Atlantis: the Lost Empire's glowing rocks were also orichalicum. Below is what orichalicum is in my fictional universe.

Introduction

"Well, at least it isn't worm poo..." - Col Chris "Ox" Jones

Explorations of an ancient South American pyramid revealed that human beings called the Quinametin discovered a way to reach for the stars. A critical component of their FTL propulsion was what modern scientists would call an exotic metal. Scientists don't know what it is since it defies conventional analysis. They only know that Plato called it orichalicum, that the Germans called it "leichtmetall" (light-metal, and alternately Xerum 525) and they knew a number of its properties.

Properties

There are a number of properties exhibited by the exotic metal. Here are the known ones.

Glitters Like Fire: The metal looks like copper until exposed to sunlight. Once exposed, it looks like the inside of the metal glitters as if a fire burned inside. Eventually the glow fades after the coppery metal reenters darkness.

Variable Density: Even stranger, in a pitch black container shielded from stray electromagnetic radiation, orichalicum is denser than iridium and much heavier than uranium. Exposed to sunlight, however, orichalicum becomes light as a feather and as dense as lithium.

Electromagnetic Converter: The exotic matter absorbs electromagnetic energy from infrared to gamma rays as well as some wavelengths of visible light. The maximum amount of radiation the metal can absorb is called its capacitance due to its similarities to electrical capacitance. The stored energy is theorized to transform into dark energy, which drains away unless used to power various effects such as bending space-time. The conversion efficiency isn't 100%; as dark energy is discharged from the metal, some energy is left behind. As time progresses, less energy can be pulled from the capacitor until it has a chance to naturally discharge. As a result, the orichalicum capacitor slowly accumulates a residual charge of energy, which creates a couple of side effects noted below.

Electronics Go Haywire: As orichalicum absorbs energy, it wreaks havoc on unshielded electronics (like what cars do during UFO encounters, where headlights and other electronic gadgets behave randomly). The greater the accumulated residual charge, the greater the effects. Near the metal's maximum capacitance, even shielded electronics will go haywire, and unshielded electronics will be fried.

Earth-Shattering Kaboom: If charged beyond the metal's maximum capacitance, orichalicum explodes rather violently. It's best to let the residual energy naturally dissipate after reaching the metal's maximum capacitance.

Uses

As Arthur C. Clarke said, any sufficiently advanced technology is indistinguishable from magic. The Ancient Astronaut technology, what is known today in the Western world as Black Box Technology (BB Tech), must've been seemingly magical to ancient societies, and orichalicum played a key role. While many uses of the exotic metal have been lost to time, the modern world has discovered and rediscovered several uses. This is by no means the definitive list; new uses for orichalicum appear periodically, while others remain classified.

Heat Sink/Radiation Shielding: Orichalicum makes a great heat sink. Shunt heat or other electromagnetic radiation into an orichalicum slug, and it glows while remaining cool to the touch.

Plasma And Radiation Deflector Shield (PARDS): By combining orichalicum with a mini-magnetospheric generator, engineers are able to create a powerful electromagnetic shield able to deflect solar radiation, just like Earth's magnetosphere does. Even better, the mini-magnetosphere can deflect plasma generated from atmospheric entry. A spacecraft would not need a heavy and/or fragile heat shield to survive the tremendous heat generated on atmospheric entry. With BB Tech, a PARDS is able to deflect small grains of sand- deflecting larger objects with more kinetic energy remains science fiction. Finally, PARDS makes an effective electromagnetic sail, though the acceleration is a paltry 0.001g.

Space-time Skipping: The Ancient Astronauts figured out how to use orichalicum to skip across space-time like a stone skipping across a pond. It takes milliseconds between skips, enabling a ship to travel the same distance in a much shorter time than it would've had it propelled itself through space-time.