Just a dumb idea I have but I will leave it up to the people to decide on this lol. I figure that if their is Aethirem in Blackreach it should be mine-able but you can only have up to 4 pieces of that stuff as with the mission Lost to the Ages to find those fragments. Also to point out if I read that girls journal correctly the Aethirem is Harmonically deadly meaning the Falmer should have been dead instead of reaching that far into Blackreach. Though the Falmer can't see they can hear and I think it is their ears that allow them to find the player the most unless you have a high sneaking skill but I digress my idea is that the Aethirem can be mined in Blackereach but only once every 3 in game months and you can only take 4 pieces of it with you to that Forge to make either the Crown, Staff, or Shield if you carry any more than 4 pieces of that stuff you will get a backlash from it blurring your vision for a short amount of that time like 40 mins minimum though their will b a ringing n the ears for a good while after carrying more than 4 pieces of it witch will be penalized for a loss of a random amount of either Stamina, Health, or Magic or you could do a combination of either Magic/Stamina, Magic/Health, Health/Stamina or a loss of a random amount of all 3 if you carry more than just the 4 pieces of Aethirem as is the number of pieces collected during the Lost Ages quest limiting the number of Aethirem items created to 1 every 3 in game months. (BTW if the Falmer can't hear you and can't see you then y the heck r they n Blackreach? If the Aethirem is so Harmonically active then with the constant ringing in Blackreach they couldn't find you at all.)