Harmonium

Harmonium, also known as ettmetal, is the God Metal of Harmony. It is used in some of the Southern Scadrians' Metallic Arts technologies. 
== Properties ==
Harmonium is the condensed elemental form of Harmony's power. Alloying atium and lerasium will not produce harmonium. While difficult, it is possible to obtain atium and lerasium from harmonium, but not through mechanical means.
Storing too much harmonium in one place supposedly can lead to the production of a perpendicularity, due to the large concentration of Investiture. Due to this, the South Scadrians make it a rule to never store too much harmonium together.
=== Chemical Properties ===
Due to the merging of Ruin and Preservation's intents into Harmony, harmonium's Spiritual aspect is in opposition with itself, leading to effects on the metal's Physical aspect, which makes it extremely reactive. It reacts violently with water, similar to alkali metals. After reacting with water, residual harmonium hydroxide is left behind, though the substance's properties are unknown. The Southern Scadrians use harmonium to create powerful bombs, which the Set have been trying to replicate with limited success. Harmonium corrodes and can react strongly in contact with the air; in order to prevent this, it is stored within oil. It does not react with acids. 
It is soft and pliable like gold, especially when heated via flame or electricity. When heated by electricity and slowly drawn apart, a nugget of harmonium begins to separate, with the two parts beginning to take on the traits of atium and lerasium. However, when the string of metal between them is cut, both sides return to being mere harmonium. 
It has an extraordinarily high melting point, above 3,000 degrees. When heated, it lets off a full spectrum of light, with the red-infrared side of the spectrum going off the spectrometric scale.
=== Reaction to Trellium ===
When harmonium has electric currents passing through it the metal softens and can be split in half. If, during this process, trellium is inserted between the two pieces a violent reaction occurs as the matter of both metals are converted into pure energy. This reaction is not complete, only converting a small fraction of the used metals into energy. The blast is powerful enough that not even Autonomy or Harmony are aware as to how strong an explosion of it can be. The explosive energy can be likened to that of a nuclear bomb explosion. Minor fragments of lerasium and atium are also produced by this reaction.
Harmonium and Trellium repel each other, with the strength of repulsion becoming stronger the closer they are forced together.
== Metallic Arts ==
The Allomantic, Feruchemical, and Hemalurgic properties of harmonium are unknown. Because of its volatile nature near water, ingesting harmonium is likely to be fatal for Allomancers, though a full Mistborn who is also able to heal through the explosive damage (e.g., by Compounding Feruchemical gold for health) could burn it for some effect. Hemalurgic spikes would also likely be difficult to create, due to the metal's reactivity; however, it is not impossible.
=== Mechanical Uses ===
In conjunction with Southern Scadrian technology, harmonium can reproduce Allomantic or Feruchemical powers within its vicinity. The Southern Scadrians use the metal in small primer cubes that can somehow regulate harmonium's effects with the flip of a switch. When used Allomantically, the metal is said to burn "with a pure whiteness" and will slowly be consumed in the same way that it would be by a Misting or Mistborn. It is used to fuel Southern Scadrian Allomantic technology, including their airships that run via steelpushing. The Southern scadrians also use it to light up rooms, using it to power blue lights. The cubes themselves are rare, since harmonium is highly regulated.
Northern Scadrians refer to the cubes as "Allomantic grenades" since they are a self-contained source of Allomantic powers once they are charged. After Wax, Marasi, and other Northerners began regularly interacting with the Malwish, they gained access to more cubes and used them to aid in their police work. The design of the cubes was also refined around this time.
It is theoretically possible to use a primer cube to reproduce other manifestations of Investiture, such as Surgebinding.
== Trivia ==
* If harmonium followed the naming conventions of the other God Metals it would have been named Sazedium. However, Sazed didn't like the sound of it.
*Brandon Sanderson has described harmonium as "super-cesium" in reference to its violent chemical reaction with water. Cesium, like other real-life alkali metals, is extremely reactive and will cause an explosion with water even at sub-zero temperatures. He later clarified that cesium was not intended as a direct analogue; harmonium would theoretically be classified as an alkali metal, although it has a different melting point.
* The Mistborn Metal Dice Set from Crafty Games lists a non-canonical description of harmonium's properties, stating "Unknown in the Classic Era, Harmonium replicates the effects of nearby Allomantic or Feruchemical metals." It also lists harmonium as an Internal and Pushing God Metal.
== Notes ==
es:Ettmetal