Metalwork as far as we know is the primary method used to make almost all dwarven crafts. We cannot, however, discount more easily destructible materials such as clay, paper, and glass from outside the scope of dwarven craftsmanship, but given the tendency of dwarven design to favor the long-lasting over the fragile, we can safely assume that at the very least metal was a heavy preference. And the metal used in all so-far-discovered dwarven relics is entirely unique to their culture.
No other race has replicated whatever process was used to create dwarven metal. Although it can be easily mistaken for bronze -- and in fact many forgers of dwarven materials use bronze to create their fake replicas -- it is most definitely a distinct type of metal of its own. I have personally seen metallurgists attempt to combine several different types of steel and common and rare ores in order to imitate dwarven metal's exclusive properties, but the only method that has been successful is to melt down existing dwarven metallic scraps and start over from there.
That's from
Dwarves v1, A book written in the fourth Era. So if 1,000 years pass from this game to Skyrim and they still say they have no idea how Dwarves made their metal, how is it that we are finding green rocks just lying around everywhere?
I'm a huge fan of the Elder Scrolls and its lore, and I've stuck with this game through multiple cashgrabs, bad game design and, at launch, many obvious and serious lore mistakes because they've stated multiple times that they want to make this like an Elder Scrolls game, and that they were "working closely with the lore guys from Bethesda". I was willing to write off Khajiit with Argonian names or the frivolous use of time travel as the fault of one or two quest developers who aren't really fans of the series and just nine to fiveing it to go home and play COD, but this is a gaping hole in the lore and as part of the crafting system, probably had many people overseeing the project and had some form of peer review, so someone, somewhere had to have noticed it.
And not only is Dwarven Ore in the game, the armor you make with it doesn't even look like Dwarven armor at all. Dwarven equipment has always been a gold-bronze color, all the way back to Daggerfall where you could find those mysterious golden swords in a Merchant's inventory. It was distinct, exciting and mysterious. So what does the Dwarven armor look like in The Elder Scrolls Online? It's green. Not even a good green, it is extremely dark and almost resembles puke. The only hint of any gold on it at all is the trim.
You might be wondering why this is a problem and you can probably tell that my jimmies are at maximum over-rustle, and they are and yours should be too. The Dwemer have always been a lost race, you could always go into their ruins for loot or just for the thrill of exploration, sometimes you would bring artifacts to people as a quest, but you never got more answers than you did raise more questions. What ZOS has done is taken away a major portion of the mystery for a faux "Elder Scrolls" feel and thrown it in our faces just expects us to accept it. As a fan of the Elder Scrolls who was promised that the game would stick to the lore, I am actually offended. I feel lied to and I feel cheated, I also feel that if ZOS actually cared about the lore, someone who did notice this back in development would have pointed this out.
So why don't you fix it, ZOS? I'm not a programmer, but I don't see why you cannot go into your game files wherever Dwarven Ore, weapons or armor is mentioned and just Ctrl+F and rename it "Unobtanium" or something. Other previously unknown materials like Calcinium and Galalite have already been added, one more isn't going to kill you, but leaving in an obvious lore error and laughing in the face if your fanbase might.