For primitive civilizations, gold and other platinum group elements are a common medium of exchange. Gold is almost universal given its inertness and therefore its non-toxic nature, but often Tantalum can represent value due to its ultimate rarity. In some more developed civilizations, Uranium or its heavier derivative elements are quite valuable. At the height of rarity is element 125 (Symbol Or) Orichalcum. For the most advanced of civilizations, the ultra-strong light-weight element has a myriad of properties that make it remarkably valuable.

A hard red metal, Orichalcum has the remarkable property of having the highest specific heat of any pure element. This means that heating the metal is incredibly difficult, requiring vast solar mirrors to concentrate enough energy to even begin melting it. As such, small impure nuggets of the substance are usually used instead of the pure metal. Orichalcum is ultra-rare, with about a kilogram existing throughout most star systems. Hanabi is estimated to have over ten kilograms of the substance distributed throughout the system, leading to a great deal of mining in the system.

Characteristics

With such a high atomic number, one would expect Orichalcum to be highly unstable. Quite the opposite is true, with the element occupying the so-called "Island of Stability" which gives its most common isotope, Or³⁰⁰, a half-life of about 10 Billion years. Its neighbor, Eitr, element 124, also occupies this island but has a half-life of several million years instead. Orichalcum is a super-actinide, but the intermingling of its electron shells has resulted in its unique chemical properties.

Orichalcum occurs natively in nature but is usually found in naturally-occurring alloys that often have high melting points and specific heat, making purification difficult. It has a strong affinity for Uranium, making most samples of the substance, even quite pure samples, noticeably radioactive.

Applications

Orichalcum is often used in high-temperature conditions and is crucial for many miniature fusion reactors that would normally be impossible. Its scarcity makes it impractical for most uses; where it is the only option, the technology usually goes unused. Within territory administered by the Occult Galaxy Project, as well as the Duchy of Royer to a lesser extent, Orichalcum is most often used by Bishops. Their ability to manipulate the metal has lead to easy plating onto other materials. Spacecraft coated in the material are difficult to assault using energy-based weapons.

Synthesis

Orichalcum is difficult to synthesize due to the ultra-short half-lives of its precursor elements. Oganesson is incredibly costly and short-lived, making aelkium, another precursor to orichalcum, all the more difficult to produce. There have been a handful of successful attempts, but the several-atom yield makes it far from worthwhile. It is unclear how natural Orichalcum formed, but a collision between two neutron stars is the most likely explanation. It is unclear which black hole was the result of this hypothetical collision. Moreover, it must have happened very early in the existence of Cosmoria, leading to equal concentrations across most of it.