tolkiens legendarium - Would Gandalf be invisible if he wore the One Ring?

If Gandalf wears the One Ring, will he be invisible? Or will he master it and be visible?

Maybe I should ask: is there a chance that the "invisibility" effect of the Ring is a side effect of weakness?

Answer

Here's an argument for no

I am going to say no because of this passage in the Lord of the Rings

‘A mortal, Frodo, who keeps one of the Great Rings, does not die, but he does not grow or obtain more life, he merely continues, until at last every minute is a weariness. And if he often uses the Ring to make himself invisible, he fades[.]

^{The Lord of the Rings | The Shadow of the Past}

Now Gandalf here is referring to the Great Rings (which we can take to include the 9 and the 7) what this tells me that any of the great rings would make a mortal invisible, not just the One Ring.

As he is saying this Gandalf is wearing one of the Three Rings and is visible. The other bearers of the great rings are elves and also are not invisible.

On the question of the great rings

The evidence is that all the great rings make you invisible (they are all dangerous to mortals).

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  The nine make men disappear, so much so that they fade and become wraiths under the dominion of The One. Although it is said in the Silmarillion that

  
  

  
  

  They could walk, if they would, unseen by all eyes in this world beneath the sun, and they could see things in worlds invisible to mortal men;

  
  

  ^{The Silmarillion | Of the Rings of Power and the Third Age}

  
  

  
  
  

  The keyword being could, can we take that to mean once they had gained mastery of the ring they could be visible while wearing it?

  
  


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  The seven did not make the dwarves invisible, nor did it give the wielder of The One dominion over them, this is because of the way Aüle created them.

  
  

  
  

  The Dwarves indeed proved tough and hard to tame; they ill endure the domination of others, and the thoughts of their hearts are hard to fathom, nor can they be turned to shadows. They used their rings only for the getting of wealth; but wrath and an overmastering greed of gold were kindled in their hearts, of which evil enough after came to the profit of Sauron.

  
  

  ^{The Silmarillion | Of the Rings of Power and the Third Age}

  
  

  
  


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  When Frodo wears the one, he sees Glorfindel's true form as it is "on the other side".

  
  

  I think that's the key, the immortal spirit doesn't because by their very nature they are already part of the spirit world and cannot be unnaturally drawn to it like a mortal.