Honorless

Oops sorry, very minor spoiler

Are you talking about those red spheres?

RoW

It's not really much as the aluminium in the hypothetical scenario is not filled with the allomancer's own Identity but it can still allow the allomancer to soothe or riot, though that might also be because the Allomancy does not come from the head but their centre, I'm assuming their stomach as they'd have swallowed the metal. Eh... the WoB might leave things open to interpretation, it's the only WoB I could find related to this theory's idea.

In White Sand? No, we haven't seen gemstones being used for Investiture storage outside of Roshar. We haven't seen that many Investiture storage objects actually, just the Polestones and the spheres from the Ire.

Oof, the burn! Something's burning and it isn't the Skybreakers' misuse of Division *Cohesionists, they'll probably be called Stoneshapers, since Cohesion was called the Surge of Stoneshaping Maybe the Nohadon story isn't true but we do get that bit in the in-world Words of Radiance where the Skybreakers were dividing the innocent from the guilty resulting in an argument with the Windrunners. The Skybreakers did take the job of policing, that's what their Ideals were themed towards. Wonder why the other Orders, some of which had powers more suited to this didn't ally with the Skybreakers towards this purpose.

Actually, this can be put to rest simply by checking if it's possible to compound aluminium. Update: only found RAFOs

I'm sure racial tension and screams of heresy and "Voidbringers" the same way medieval Earthlings screamed "demons" or "witches" solved that problem

And that is how the Skybreakers lost their jobs, kids! *damn, outta my 20 upvotes limit again, just you wait, will come back later, you've earned it* done!

Probably forgotten due to the Desolations and knowledge not distributed by the Knights Radiant after Aharietiam.

Yes there is that problem. Feruchemically it only covers a faux storing, no tapping. It is possible that this is a power that Feruchemists thought they just haven't been able to use properly and/or is dangerous because tapping seems to be so difficult that no one's managed it. The creation of unkeyed metalminds could also, arguably, work with this. Hemalurgically, aluminium doesn't steal anything, it just removes all powers of the spiked. Allomantically it removes all ingested metals, which is a bit weird because it's removing something physical rather than just the Allomancer's ability to burn their ingested stores of metal. Btw, I found this WoB, I think it might support your theory:

A small theory that I think got some solid support with RoW. So we saw in Rhythm of War that the Allomantic/Feruchemical/Hemalurgic metals have functions outside of the Metallic Arts and are one of three key components in fabrials alongside spren & gemstones. It makes sense, metal acts as a key for Allomancers to access Preservation's Investiture. Without Allomancy in your Spiritweb, you can't access that Investiture but you should still be able to use the metal to filter other Investiture that you do have access to. That is kind of similar to how the Polestones themselves function, why they can hold Lights Their small differences in chemical structure & colour is all that is needed for Investiture to distinguish them. An element's atomic structure absorbs and reflects different wavelengths of light (or Light), the light can be used to identify those atoms & molecules. A metal's structure is used as a filter for Investiture, the same probably goes for a gemstone. Colour is more important magically for gemstones but this is what the colour of an object means in physics & chemistry, their molecular structure would be a bit different. A metal acts as a filter and lets Investiture through and a gem both filters it (what gem you use does matter for Soulcasters and Artifabrians) and holds it. So, gemstones should, like metals, work across the Cosmere, and be able to hold other types of Investiture than just the Rosharan Lights. Idea came from here: Edit: we have confirmation that the Mists can be trapped in gemstones Edit: in the Brandon spoiler livestream at 33:20, Brandon confirms that Autonomy's Investiture can be stored in the Polestones but he isn't sure if that is something that could happen naturally (but it could definitely capture the Dor) and even if it does, it would be very ineffective, maybe it would store very little bit of charge that would only be perceptible to someone with the right instruments and it would soon dissipate. I've noted previously in discussions that White Sand requires surprisingly little Investiture to recharge. I think the oldest instance of this theory is here: While it takes four hours for black sand to recharge back to white sand on Taldain's Dayside, just proximity to Shallan's Lightweaving was enough to charge Hoid's white sand in OB, this happened when Kal, Shallan, Adolin and Elhokar went to Kholinar. In the very same section and following section that took place in Shadesmar, it is noted that Shallan's Lightweaving used far less Stormlight than Kaladin's Lashings. Keep this in mind. I do have an idea on why White Sand could apparently recharge from Taldain's sunlight or apparently even from very far from its starlight as per a prev WoB, but would be difficult to store in a gemstone. In RoW, we see Navani use a prism to separate the light emitted by Towerlight back into the bands of Stormlight and Lifelight, she notes that she didn't separate the Lights or the Investiture, just the "Investiture radiation". I think that's what Taldain's sun outputs: not gaseous Investiture but Investiture radiation. And that's why it outputs so little Investiture that it takes black sand exposure to direct sunlight for four hours in order to recharge and turn white again but Stormlight, even sheer proximity to a Lightweaving, which in itself is noted to use much less Stormlight compared to Surge of Gravitation.

Probably not, we have this WoP:

Shards not being able to stop people from using their Investiture was kind of funny but narratively, I can see why making it be otherwise would've made Shards a lot more difficult to deal with in the story and thematically. Should note though, Adonalsium probably didn't create the universe, only the Cosmere, which is a relatively small star cluster. Cool tidbit: someone once tried to leave the Cosmere Brandon said something about Braize and Roshar being in the Greater Rosharan System, and all the planets within the system being within reach of the resident Shards' influence

There are a few WoBs which imply Seons might grant some benefits to whom they're Bonded to, like the spren I'm sure their Knights breaking their Ideals had consequences for the spren back then too, just not as dire as becoming a Deadeyes

Yup, Silver is what I had in mind! Water might be important to Taldain, not sure about silicon, as it's not the sand itself that's magical but the microorganisms living on it. As for the last one, I think that has more to do with Investiture tending towards sentience, objects having a Cognitive... something and stemming from it, things that used to be alive wanting to be alive again. I'm not sure that might have anything to do with Investiture reactivity. But more importantly, I was wondering if gemstones should be able to store other kinds of Investiture.

The stones would remember that humans arrived from elsewhere. RoW and recent WoBs seem to indicate that the Recreance wasn't just an emotional response but a plan. We're still missing some critical info. I recall the Stormfather mentioning in OB that when Honor was there, he consoled the Radiants who discovered the truth of the human Voidbringers and the native Parsh people.

On the Identity and Connection thing. @Eternal Khol once pointed out that it's called a 'Spiritweb', possibly a web of one's Connections to people, places, things defining who they are to the world.

I think this checks out. Metal acts as a key for Allomancers to access Preservation's Investiture. Without Allomancy in your Spiritweb, you can't access that Investiture but you should still be able to use the metal to filter other Investiture that you do have access to. An element's atomic structure absorbs and reflects different wavelengths of light, the light can be used to identify those atoms & molecules. With metals whose structures are used as filters for Investiture, maybe they could do the same with Light, and Investiture in general. This is interesting because this suggests reactivity between matter, energy & Investiture. Which might mean that other chemically mundane substances that may not be Allomantically viable might react to Investiture in certain ways.

Well there is this idea by Paleo regarding how aluminium might seem to be Feruchemically viable: Kinda like how the Steel Ministry misunderstood what Atium could do during the days of the Final Empire But you've got me swayed, Oltux

I interpreted that as him using his Surges. Dalinar could use a Spiritual version of Tension & Adhesion to repair or keep together structures in the Physical Realm or in the Visions. Adhesion to manipulate Connections. I thought this was Tension on the surface on his hands for grip strength, possibly also Adhesion to stick to surfaces. We don't really see any spren congregating around Dalinar during that scene. He doesn't already have a Bond with his Order's minor spren, suspected to be Gloryspren, to create Shardplate. The first time the Plate manifests, we should've seen the spren, after that they can remain invisible, and become visible on command, as we learned in RoW. We do have a Gloryspren congregation but that happened later on during the Unity moment. The Vision was happening close to the Spiritual Realm though, so it's possible the spren were there and we just didn't see them. Since Shardplate aren't made from the Godspren themselves, Bondsmiths might be able to have Shardplate. Hmm... though the Stormfather does say that he'll be "a Radiant without Shards".

Good point, Investiture level & how well a spren can manifest in the Physical would probably be important to this, for both Syl & Pattern, distance wore their minds out, but the Highspren seemed capable of more distance and being more in the Cognitive Realm. Speaking of Highspren, wonder if they'd be better for double Bonded Radiant: like Skybreakers have to follow a code, right? What if those codes were the Ideals of another Order? Oh yeah, the Seon Bond? Didn't Brandon say a Seon Bond could give powers like the Nahel Bond on Roshar? Oh yeah, they seemed to have forgotten even the fact that one became Radiant by Bonding a spren. Interesting idea. Would it really save the spren though, I think they'd need to be able to sever that Bond. These aren't small Connections, a Bonded spren and their Knight Radiant's Spiritweb merge a bit together. I think this puts the spren in more danger of broken Ideals rather than giving them an option 2.

Oh yeah, now we have an in-book example of someone with two Bonds! Even if one of the Bonds has deteriorated, and both Bonds are to the same type of spren. Hope we see more of double Bonds! (but not too much, otherwise it might become Stormlightball Z) Radiants sharing a single spren between them probably hasn't happened ever. Kaladin's Windrunners wouldn't have known, otherwise the shortage of Honorspren willing to Bond wouldn't have been an issue. Nale might or might not have known if something like this was possible but I don't think the Skybreakers have a shortage of Highspren. No mention of anything like this in pre-Recreance texts. One spren with two Bonds... I think spren can look at multiple candidates but would both start approaching Radiancy? I don't remember seeing anything like that. We've seen Bonds shift between people (Eshonai to Venli), and Bonds between multiple people (Knight and Squires) but that's not really enough to say anything on this idea. It might be too strenuous on the spren, psychologically & magically, who might get ping-ponged back and forth? This is probably something that could technically happen but why would a spren do that? kind of case, like Bonding a Hemalurgist. Or something the spren simply haven't considered as it doesn't offer any advantage and/or don't know that this is something they could do in the first place, or they just don't want to or it might go against their nature (like spren of different types Bonding the same Radiant or a Bondsmith spren becoming a Shardblade). I would say it's probably possible but not advantageous nor comfortable for the spren. Currently the spren would also be under double the risk of becoming Deadeyes

no? Elend's crown then

I like it! It's way better than the child champion theory at least. Odium & Dalinar's deal is very specific in Odium not being free regardless of who wins, and I don't think getting a draw would result in the contract being null & void. So that does leave Odium letting Dalinar break the terms of the deal somehow being the most feasible course of action as far as I can tell.