Aluminum

Aluminum is the internal enhancement pulling metal. An Allomancer burning aluminum will make all of their metal reserves vanish. Feruchemists can use aluminum to store Identity, and when used as a Hemalurgic spike, aluminum removes all powers. It is known as Ralkalest in the Rose Empire on Sel and among singers, as the unForgeable metal in the Rose Empire, and historically as starmetal in Azir.
Aluminum has been confirmed to have strange effects to all magic systems, is magically inert, and will act as an Investiture block.
The paired alloy of aluminum used in the Metallic Arts is duralumin.
== Allomantic Use ==
An aluminum Misting is known as an Aluminum Gnat. Burning aluminum causes the body to instantly metabolize its metal reserves—including the aluminum itself—without any other effect. As such, an Aluminum Gnat gains no useable powers from their Allomancy, however, it can be used to negate effects of other Investiture, such as the withering effect of Shades on Threnody. Only Allomantically relevant metals can be burned away. Allomancy does not affect aluminum even though the metal itself is Allomantically viable.
=== Savantism ===
If someone were able to burn the amount of aluminum needed to become an Allomantic savant with the metal, it may be possible to cleanse their spirit of unwanted effects of Investiture.
== Feruchemical Use ==
An aluminum Ferring is known as a Trueself. Aluminum is used to store "spiritual sense of Identity." This ability is not fully understood, and is rarely discussed outside of Terris communities. A Trueself who fills an aluminummind to the point where they have no Identity and then fills another metalmind is able to produce a metalmind that any Feruchemist with the relevant power can tap. In a similar manner, a Feruchemist may be able to tap another person's metalminds by filling their own aluminummind completely. Trueselfs can heal damage done to them in the Cognitive Realm by storing Identity, but it takes a roundabout method. Storing Identity makes the Feruchemist more susceptible to many things, such as Forgery.
It is unclear why Identity can be stored in and withdrawn from an aluminummind when other Invested Arts cannot affect aluminum.
== Hemalurgic Use ==
When used as a Hemalurgic spike, aluminum removes all powers, such as Allomancy or sand mastery.
== Weaponry ==
On Scadrial, guns and bullets made from aluminum are highly effective (albeit expensive) because they cannot be Pushed, Pulled, or even detected using the sight granted by steel or iron Allomancy. Aluminum bullets are actually composed of an Allomantically inert alloy of aluminum since the ballistics of a pure aluminum bullet would not work.
== Investiture-inert Properties ==
While aluminum doesn't always directly negate all magic systems, it does have very weird, interesting effects in all places. A person having aluminum in their body would interfere with many magic systems in some way. Alloys of aluminum get some of the Investiture-inert properties of aluminum.
=== Scadrial ===
* Allomantic Iron/Steel: Pushing or Pulling on aluminum will do nothing.
* Allomantic Pewter: If an aluminum object is stuck inside a body, it is impossible to use pewter Allomancy, making it impossible for wounds to heal around the aluminum until it is removed from the body, however the effect would not be too severe on the Thug, as they still have strength. There is a similar and more severe effect on gold Feruchemists.
* Allomantic Zinc/Brass: Aluminum can shield people from emotional Allomancy. Because aluminum can shield against emotional Allomancy, those who can afford to often wear hats with an aluminum lining.
* Allomantic Bronze: Aluminum hats can be used to block Seekers from using bronze on them.
* Allomantic Bendalloy/Cadmium: An object made out of aluminum can create dead zones within cadmium and bendalloy bubbles, where the shielded area is not included within the time bubble. 
* Allomantic Atium: Objects made out of aluminum generate no Atium shadows.
* Hemalurgic spikes: It is possible that encasing Hemalurgic spikes in aluminum may prevent Hemalurgic decay.
* Primer cube: If used in a primer cube, aluminum would block the use of Invested Arts within a certain range.
=== Sel ===
* Forgery: Aluminum cannot be altered at all via Forgery.
=== Roshar ===
* Surgebinding: Aluminum cannot be affected by the Surges Adhesion or Gravitation. It interferes with most Radiant powers. Aluminum can be produced with Soulcasting. However, aluminum resists attempts to Soulcast it into other Essences. It can prevent Soulcasting from being detected by others.
* Shardblade: Shardblades are unable to cut aluminum through magical means but would be able to cut it physically, like a conventional blade, if the aluminum were thin enough. A room lined with aluminum can also stop a shardblade from being summoned.
* Fabrial: Aluminum can block spanreed communication. It cannot prevent Light leakage, as it is leaking directly into the Spiritual Realm. Aluminum interferes with the spren's ability to sense thoughts. By placing aluminum foil in a fabrial, each axis of motion and rotation could be blocked separately by proper application. This allows certain, but not all, functions to be blocked.
=== Nalthis ===
* Awakening: Aluminum cannot be Awakened.
* Returned: It is possible for aluminum to prevent someone from Returning, but not simply by stabbing the body: aluminum is inert and blocks Investiture, but does not actively absorb it. 
* Heightening: Aluminum can block an Awakener's life sense.
=== Lumar ===
* Silver: Aluminum is said to "block" the effect that silver has on Aether spores.
=== Cosmere ===
* Shard: Wearing aluminum can help a person resist the influence of a Shard.
* Perpendicularity: Aluminum can be used to take liquid from a Perpendicularity, and it will stay Invested.
== History ==
=== Rose Empire ===
Aluminum is known as ralkalest in the Rose Empire. The cells for Forgers in the Rose Palace have ralkalest grates in their ceilings for entrance and a thin plate of ralkalest behind the stone walls.
=== Pre Catacendre ===
The Lord Ruler kept aluminum and its alloy duralumin from public knowledge to give the Inquisitors an advantage. During his rule, aluminum was harvested from the Ashmounts.
=== Nalthis ===
Nightblood's sheath is made of aluminum.
=== Roshar ===
The Knights Radiant once lined tunnels deep beneath Urithiru with ralkalest, likely to protect against intrusion into the tunnels from the foothills below via Surgebinding. It is unknown whether the term ralkalest is of Selish origin alone, or if Raboniel learned of it from another source.
The Unkalaki people are able to obtain aluminum by trading with the spren world, and are aware that it has an effect on spren.
Highmarshal Azure was given metal sheets by Wit during her time in Kholinar that were possibly aluminum. When lining a room, they allowed for the use of Soulcasting fabrials without detection by the Voidspren. A Fused used Nightblood's sheath to block an attack from Szeth, who was wielding Nightblood.
An aluminum box was used to secure the gemstone containing Nergaoul, which was then sunk to the bottom of the ocean, to prevent the Unmade from being released again.
During the expedition to Aimia, Rushu is tasked by Navani to experiment with aluminum and discover the details of its impact on fabrials. They first note that the thickness of the metal may impact its effect on fabrial operation (e.g. block vs modify). After tinkering with a spanreed and aluminum foil, Huio theorizes that the spren react to aluminum "almost like prey react to a predator" and that it interferes with the spren's ability to sense thoughts. Rushu further theorizes that each axis of motion and rotation could be blocked separately by proper application of aluminum. It is likely that other types of fabrials (i.e. heating fabrials) could be modified similarly.
This experimentation accidentally resulted in a series of modified fabrials in which the mechanism contained bits of aluminum foil that blocked certain functions, but not all. Among these were a spanreed that transferred lateral motion, but not vertical; a lift to permit Rysn to move between decks of the Wandersail and a number of "wheelchair" fabrials which levitated and permitted Rysn to maneuver while seated using a partially aluminum-blocked counterweight. These are particularly useful due to a known drawback of motion-transferring fabrials caused by a moving frame of reference (e.g. a moving ship at sea communicating by spanreed to shore).
Odium's forces later lined their weapons in aluminum to protect against Shardblades.
=== Post Catacendre ===
A significant percentage of the aluminum in the Basin is produced by the Ghostbloods. Dean, the Scadrian branch's chemist, believes that the Scadrians would one day discover how to create it via electrolysis, and that the value would plummet to being cheaper than tin. The Ghostbloods have been using their aluminum to fund their operations for the past two decades. During and , due to advances in aluminum production technology and processes, Scadrian aluminum dropped in price, though it still remained expensive and unaffordable to most people.
=== Lumar ===
Aluminum lined rooms and boxes are used to protect Aether spores from silver.
== Trivia ==
* Brandon thought of having Vin burn silver rather than aluminum when captured in Kredik Shaw but decided that aluminum would be less abundant.
* Brandon chose aluminum for the role it serves because it is rare pre-industrial age, then becomes incredibly common, providing a way for technology to counter Allomancy.
== Notes ==
es:Aluminio