Mirrorsteel is a name I made up, yes, but it is a name made up for stainless steel.
Silversteel is not any real alloy, so alright, I'll add an "unreal" ingredient to the mix.
Here's the complete change list for metals:
-Chromium. Decorative metal. Smelted from chromite (requires aluminum) or from native ores.
-Magnesium. Ingredient metal. Smelted from powdered dolomite, requires carbon.
-Manganese. Ingredient metal. Smelted from pyrolusite.
-Molybdenum. Rare ingredient metal. Smelted from molybdenite, a rare mineral present in chalcopyrite veins in granite and diorite.
-Cementite. Not technically a metal, but qualifies as such as it is a byproduct of smelting pig iron or steel.
-Kelshinral, "Silvershine". Decorative metal, valuable, rare. Smelted from "Lamshinral", a rare ore found in silver and aluminum deposits.
-White gold. Decorative metal. Smelted from gold and nickel.
-Silversteel. Similar in performance to steel, yet a lot lighter and slightly more valuable. Smelted as steel with addition of Kelshinral.
-Kerasteel. Slightly harder than steel. Is, in essence, steel retempered in presence of cementite.
-Magnalium. Aluminum hardened with magnesium. Used for armor and ranged weapons. Lightweight, yet noticeably worse than iron.
-Duralium. Aluminum hardened with manganese and magnesium. Used for armor and ranged weapons. Lighter and harder than magnalium.
-Mirrorsteel. Steel forged with nickel, molybdenum and chromium. Much more valuable and noticeably harder.
There is going to be one more, I just need to finalize a name for it.
I may have reversed the dural/magnal relation (in that magnal is harder that dural, as per the wiki), but the name "duralium" sounds "harder", so to speak.
I also allowed certain noble metals to be used in ammo and weapon construction - namely, silver, gold, aluminum (armor too), and lead (ammo only