Overlooked use of metals in fabrials

[+Oltux72 he/him]

I think I now know what zinc/brass are used for and I feel stupid. Navani mainly works with cojoiners. A spanreed does have a cage. It is natural for her to start her lecture with them. You need something that does the the off-blink-read-write setting on a spanreed. That effect can be very well be described as a spren affecting the physical realm in terms of force, not Arcane Effect. In other words, the spren manifest (physically). That's what zinc and brass do. They are the on/off switches for cojoiners. Heatrials and the augenters/diminishers in general work with pewter/tin, not zind/brass.