What (potentially) can Minor Conjuration do?

[Darth Credence]

Korvin, those first four would all fall under "a container of liquid". For the last, obviously you could make a pearl, but the relevant question there would be whether you can sell it.

Darth Credence, some of them seem easy to me (like, I definitely wouldn't allow someone to cast Raise Dead with a conjured diamond, even though the strict RAW would seem to allow it), but others I'm much less sure about. Like, the key that the wizard saw hanging on the guard's belt: There's an argument that the wizard can't remember it well enough, but there's also an argument that it must take the exact form of an object the wizard's seen, so they can't get it a little wrong even if they try.

Or take the illusion question: On the one hand, if you can make something you've only seen an illusion of, that allows you to make an object that never actually existed. But if you can't, then it turns the ability into an illusion-detector. Neither one of those seems entirely within the intent of the ability.

I think the primary reason for "that you have seen" is to prevent people from making smartphones or laser pistols or the like (because you know that someone would try that). But it also gets to a question of how the ability actually works: Are you conjuring the metaphysical essence of a specific existing object, or are you crafting it yourself out of magically-conjured material?

For the key that the wizard sees hanging from the guard's belt, I would say that the wizard did not actually see the entire key. There could be an argument about how the guard was moving and how long they looked, so I'll explain my reasoning slightly differently. Let's say that the wizard has been captured, had special mittens that prevent somatic components put on their hands, in a cell with several glyphs set up to cast silence in the area if anyone starts saying magic words, and a bag over their head. The door is shut behind them and the key is left hanging on a hook, such that one side is facing the cell and the other is facing the wall. The wizard gets the hood off, and looks out at the key. They can see half of it clearly, including all of the grooves that will be involved in unlocking the door. But what they cannot see are the grooves on the other side - it could be smooth, two grooves, whatever. So if they tried to conjure that key, they would not have the information to get all of it. Therefore, I would say that they cannot conjure it. Now, if they didn't have a hood, and could watch the door being locked, they could have seen everything about the key and duplicated it. That, to me, covers your possibilities - yes, they cannot make a key "wrong", but if they don't have all of the information about it, they don't fulfill the requirements to make it at all.

For the illusion part of it, is it an illusion detector? Maybe, but not better than a stick. If we say you cannot recreate an illusion, then yes, the ability would fail trying to recreate one. But for that to be an illusion detector, it would only work on illusions that appear to fit within the parameters of the ability (less than 3' and 10 pounds). That's pretty limiting on it's own, but not the most limiting. So you think the jeweled chalice on the table is an illusion. You look it over and try to create one. If it works, OK. If it doesn't, it was an illusion. Great - but wouldn't poking the chalice with a stick have told you the same thing quicker? And are we sure it would tell you it's an illusion, and not that it's magical? You can't recreate a magic item, either, so if that cup is enchanted to keep drinks cold, you can't duplicate it.

As to whether the call is easy, I did not make myself clear. I personally think the call is easy so I have a hard time coming up with appropriate questions. What is "easy" for me may be blind spots I have to what makes it difficult, long experience at making these kinds of calls, or sheer hubris about my abilities - who knows? I did not make that clear before, and I should have.

Depends on the results of the deception roll, I suspect.

I'd set that DC at 30, since it is visibly glowing enough to shed dim light for 5'.