As I read Oathbringer, I got really excited about something that may seem insignificant and I think people are glossing over it (although, there may be a thread that I was unable to find - If so let me know!). In chapter 81 of Oathbringer, we find out about how the Wall Guard was able to Soulcast food without the Screamers noticing. Hoid had brought a metal, which almost certainly is aluminum, to Kholinar and told Azure to only do Soulcasting inside a room lined with it. And Spanreeds were unable to connect to the outside. This in itself made me super excited. Aluminum on Roshar! Hoid is brilliant.
Okay, but it made me wonder. Aluminum is extremely valuable for its abilities to block emotional allomancy, and if it can block all kinds of long distance investiture and such, that's amazing. And aluminum is hard to produce, at least basically everywhere in the Cosmere at this point in time, but it won't always be that way. Aluminum was once one of the most difficult metals to purify in our world, but now it is ubiquitous, this makes me wonder about the massive economic and investiture/magic advantage a world will have once it can refine aluminum easily. I think that the power of aluminum will be fascinating, particularly as it has only done relatively small things so far. And at some point, it will be common. There could even be things like aluminum tanks!
What do you all think about this?