Minor Conjuration is an interesting ability that Conjuration Wizards get. It can be found on page 116 of the phb and it seems to be a point of confusion for many players asking “What can it do?”, so I’m here to help. This is of course my opinion and your DM may have very strong opinions about this ability that are opposite to this, but this is based on game design and intent and what a reasonable person could expect it to do.

The actual wording of the ability currently is : 

Starting at 2nd level when you select this school(conjuration), you can use your action to conjure up an inanimate object in your hand or on the ground in an unoccupied space that you can see within 10 feet of you. This object can be no larger than 3 feet on a side and weigh no more than 10 pounds, and its form must be that of a nonmagical object that you have seen. The object is visibly magical, radiating dim light out to 5 feet. The object disappears after 1 hour, when you use this feature again, or if it takes or deals any damage.

Most people get the idea of what this does but a lot of people are trying to make this ability as powerful as they can and it’s creating a lot of debate and confusion. Let’s start by saying that this is intended to be a non-combat ability to add interest and flavor to your hero. So frame how it works through that idea. Some guidelines and advice are that you can create:

-any normal everyday object in your particular fantasy world (like a chair, reading glasses, shaving razor, pocket watch, a pillow, etc) or an item on the equipment list in the phb as long as it’s lighter than 10 lbs and smaller than 3 feet on a side

What about a coil of rope? Or a coil of silk rope with a grappling hook attached ? (Both fine, 50 ft of rope you can’t cut without disappearing isn’t going to break the game)

What about a flask of acid, oil, holy water, anti-toxin, tankard of beer, bottle of fine wine or water, etc? (All are fine, just remember if it does damage it disappears, so an easy rule: your flask of acid, poison, etc. does 1 damage to 1 Creature and disappears. If that’s how you want to spend 2 actions (1 to conjure it and 1 to use it), then Go for it. There are better ways to do damage)

What about a bag of caltrops, quiver of 20 arrows, bag of sand, ball bearings, smith’s tools, lock and key, etc? (All fine. I don’t care that there are 20 caltrops in the bag or there are many items in the smiths tools. It doesn’t break anything to conjure 1 of something you can buy in the phb) and if any caltrop/arrow does any damage it’s 1 hp to 1 Creature and then they all disappear. 

What about a bag of 100 gold, or diamonds, etc (okay you won’t find any of these for purchase in the players guide so your DM can overrule this but I’d allow it. Merchants aren’t any more likely to accept your glowing bag of gold coins than a 10lb glowing ruby. You would be better off forging fake money and using that. Plus ripping people off is a great way to make enemies and to get arrested and have ALL your posessions confiscated by the cops.)

What about Book, spellbook or an enemies spellbook? (Fine, if you read the book cover to cover then yes. It’s not overpowered because if you had the time to read an enemy spellcaster’s SpellBook cover to cover, then you probably could have just stolen it and copied the spells anyways. Also DM’s control the spells you find in spellbooks. If hey don’t want you to have access to the spells, they just don’t put them in the spellbooks you find. And you still need to decipher the spells and spend the 50gp and 2hrs per spell level to copy them to your own spellbook to use.)

What about a piece of the sun, black hole, radioactive metal, etc? (Don’t be silly, a piece of the sun, black hole, etc. isn’t a object any more that a piece of a fire is an object. And these are OBVIOUSLY well outside the scope of what this ability was intended to do). Keep in mind that “seen” to a reasonable person means that you have been personally close enough to observe/inspect something. If you were close enough to personally inspect any of these then you would be dead. Remember: intended to be non-combat & to add flavour and interest to your wizard.            [ P.S. -If your player really wants to push for this ridiculousness, then fine: your radioactive metal does 1hp of damage to 1 Creature and then disappears ]

What about the key to my jail cell or to my house or a locked chest? (All fine. If you were reasonably close enough to the key to see it and know it’s the proper key, then this is a great use of this feature. I don’t care how complex or detailed the key was or that you saw it a while ago back in Waterdeep. It’s not going to break your game. If the DM doesn’t want you to get out of the cell, or into the chest, then he/she doesn’t have to let you see the key.)

What about healing potions, spell scrolls, etc? (No, those are magical)

What about shield, armor, weapon? (it’s fine, these things aren’t damaged from being used as intended. Damage is a specific game term relating to loss of hit points. If the DM doesn’t have you roll for hit point loss on your shield or armour, then it isn’t damaged. Remember for a weapon, the instant it does any damage it disappears, so your conjured longsword hits the orc and (easy rule) does 1 damage and ‘poof’ it’s gone. I’m fine with slings, bows, crossbows, pistols, etc being used without disappearing, but not the ammunition)

What about spell components: 100 gp Pearl, a 5000gp Diamond, a bag with 50gp of ruby dust, a gem-encrusted bowl worth at least 1,000 gp, etc? ( It’s fine. If you seen a 5000gp diamond and it weighs 10 lbs or less, then do it. Quick and free spell components is a great use of this ability and adds some oomph to picking a conjurer over an abjuration wizard for example. This won’t break your game. Heck, make all the continual flame torches you want with the ruby dust and corner the market selling them. Sounds like a great downtime activity for you and your DM to create a story out of.)

What about Mithral, Adamantine, Silver, etc? (It’s fine. Keep it under 3 feet and less than 10lbs. and you have to have seen it. You want an adamantine lock or a mithral shield or Beholder-hide saddlebags, then go for it.)

These are some tips and guidelines to help lift the confusion and “what about....” questions and debate that come with this ability. This is just for players/DM’s who are a little lost and want some direction. If you don’t agree with any or all of what I’ve said, that’s fine. Don’t use this mini guide. It’s not for you and I won’t make you. Also don’t bother commenting (good or bad or neutral) because I’m never going to read them. Nothing personal, I just never check these things.

Jeremy Crawford himself deconfirmed this, saying that if you conjure a weapon and hit something with it "It does not disappear"

Basic healing potions are non-magical, greater and above are magical

He also said that "These Items are a magical facsimile and have no value"

Sorry to correct you after you spent so much time and effort, but I wanted to clarify

No worries I appreciate you taking the time to read the guide. This post was to help local gaming groups and explain the feature for DM's and to help curb player shenanigans like trying to conjure a piece of the sun so they can destroy the planet type stuff.

For the weapon: yes you can hit someone with it and it wont disappear, but minor conjuration says "The object disappears... if it takes or deals any damage." So if you hit them and do damage with your conjured weapon or item, it does disappear. And I don't see the point in hitting someone with a weapon if you don't intend to do damage. Perhaps for role playing or a deception maybe.

For the Healing Poitions: The regular Potion of Healing are common items but their stat block describes all healing potions as a "magical red fluid" . Its easy to mistake a common item as being non-magical but that is not always the case. There are lots of common items that are also magical. A Shield of Expression for example, or Clothes of Mending.

For Conjured items have no value: this is totally correct. This is more of a DM judgement call. The "no value" stipulation is to keep players from selling the item or using it as a currency. For my game I go by Rule of Fun and I have no problem saying that if the wizard saw a 100 gp Diamond and conjured it, that they couldn't sell it or use it to pay off a debt because it has no value, BUT that they can still use it as a spell component. This is up to the DM however. Its a bend of the RAW but not a game breaking one. Towards the later game when you need a lot of the more costly spell components money usually isn't much of an issue anymore anyways. Plus it just feels thematically appropriate for a conjuration wizard to just conjure their own spell components.

Obviously this is just what I think. Run your game however you want. You can use all of what I said, some of it, or none of it. Whatever makes your game suit you and your friends is how you should play. And keep asking questions if something doesn't seem right to you. It helps us all get better. Cheers and Keep Rollin those Dice

Sage advice is advice from the developers based on the written rules. And the only quote I ever seen about this from Jeremy Crawford was in regards to whether using a conjured weapon in combat damaged your weapon and made it disappear as per the rule. He clarified that using an item for its intended purpose doesn't damage that item in game terms. Damage is a game term that describes the loss of hit points. A sword hitting something does not lose any hit points itself, thus it takes no damage. This doesn't erase the rule that if the sword deals any damage to something that it will disappear however.

Dario Berto ‏@Uzedh · May 5
@JeremyECrawford If I conjure a weapon with Minor Conjuration and I hit a creature, does the weapon take a sort of damage to disappear?

Jeremy Crawford

@Uzedh No.

Regardless Your DM overrules everything in their game no matter of what sage advice may say. I'm just going by what is actually written down in the rulebooks to give people a direction for what they could do. Healing potion says that it is a magical red fluid so that's what I'm going with:

"A character who drinks the magical red fluid in this vial regains 2d4 + 2 hit points. Drinking or administering a potion takes an action."-  right from DnD Beyond.

No where in the description did it say that they were made of painkillers and herbal drugs but if they are in your world then that's awesome. There is also nothing saying that mix of painkillers and herbal drugs couldn't be magical in a fantasy setting. Lots of magical plants and herbs in D&D. Ed Greenwood has some wonderful write-ups for them if you play in the Forgotten Realms setting. Or maybe your world had a unique non-magical kind of common healing potion. Sounds like a fun and interesting take on it. Its the same if you want to conjure magical weapons that can do damage. The ability says it disappears if it does damage, but if in your world or your specific wizard changes that, then perfect. It doesn't break anything in my opinion if you want you wizard to conjure a magical longsword to use in combat. Go with what makes your game fun and a better story. I still would caution on giving players the freedom to magically create your "common non-magical healing potions". Infinite on demand healing potions I would consider game breaking. Its one of the reasons why the developers worded it the way they did.

Quote from Ajexton >>

-any normal everyday object in your particular fantasy world (like a chair, reading glasses, shaving razor, pocket watch, a pillow, etc) or an item on the equipment list in the phb as long as it’s lighter than 10 lbs and smaller than 3 feet on a side

What about a coil of rope? Or a coil of silk rope with a grappling hook attached ? (Both fine, 50 ft of rope you can’t cut without disappearing isn’t going to break the game)

 I suspect you'll find that 50 feet is significantly larger than 3 feet.

It's not 50' when it coiled. It easily fits in a 3 foot box. Whether that is acceptable is a GM call.

Quote from stringless >>

Quote from Ajexton >>

-any normal everyday object in your particular fantasy world (like a chair, reading glasses, shaving razor, pocket watch, a pillow, etc) or an item on the equipment list in the phb as long as it’s lighter than 10 lbs and smaller than 3 feet on a side

What about a coil of rope? Or a coil of silk rope with a grappling hook attached ? (Both fine, 50 ft of rope you can’t cut without disappearing isn’t going to break the game)

 I suspect you'll find that 50 feet is significantly larger than 3 feet.

 I suspect that you will find that rope is flexible can coil up to quite easily fit inside a 3 foot cube. Unless where you are rope doesn't coil up is then more of a pole and would then not meet the criteria for the ability. Although I did not have a problem with a player who wanted to make a collapsable pole similar to a tent pole. The point of that statement is that there is nothing game breaking by letting your conjuration wizard create one. Its useful, fun and good for the story. Its totally reasonable for someone to say that 50 feet of coiled rope would fit in the 3 ft. cube. Of course that call will still be up to your DM in your game. These are simply suggestions that you can use or not. So long as you and your friends are enjoying the game, that is all that matters to me.

From the phb pg. 116 "The object disappears after 1 hour, when you use this feature again, or if it takes any damage." It says nothing about dealing damage. You might have misread that part. 

Quote from BladeBeast17 >>

From the phb pg. 116 "The object disappears after 1 hour, when you use this feature again, or if it takes any damage." It says nothing about dealing damage. You might have misread that part. 

 
From the updated (errata'd) PHB (emphasis mine): "The object disappears after 1 hour, when you use this feature again, or if it takes or deals any damage."

ig the new ones changed it, I did not know that.

I take issue with conjured items only doing 1 hp worth of damage. if you conjure a longsword and hit, it should do whatever rolled damage a longsword would normally do THEN disappear. spells and abilities only do what they say they do and nothing more or less. whatever you conjure has the exact same properties as a real object that wasn't conjured with the mentions caveats. nothing about the spell says its only meant for non-combat situations or has to be a everyday object. inversely i think things get a bit funky when you start talking about groups of items that are categorized as one item by the phb or items of value. I wouldn't let my player conjure a bag of caltrops because first of all, the bag is its own object, and each caltrop is a single object. and if you let players conjure objects of value, then you run into the trouble of "hey I conjure the 25,000gp component we needed to cast true resurrection" which gets REALLY cheesy and I feel isn't what the creators intended. Plus I could reason that as soon as they start casting, the spell begins to consume the component which counts as damaging it and it disappears before it can complete and the spell fails. spells with non-valuable components or valued components that is does NOT consume I could MAYBE allow, but it still feels a bit cheesy. This next part is my personal rule, but I also feel like you shouldn't be able to conjure something you don't know the workings of. like you cant conjure a flask's worth of acid if you don't know how acid is made. and just so I'm clear again, youde only be conjuring the acid itself, not the flask which contains it so as to be consistent with the "you can only create one object" part of my comment. you could conjure acid into an existing flask, or you could conjure and empty flask, but not both.

Quote from companyoflosers>>

I take issue with conjured items only doing 1 hp worth of damage.

LoL, No need to ‘take issue’ I don’t believe the post personally attacked you in any way.

Joking aside, However you want to run this ability in your game is fine. You should feel free to run your game however you wish. And I love that you want to be creative with it. This is just a guide to help people who need some direction and to help curb things like players trying to conjure the sun and what not. If you already have a direction you like and an internal logic for this working as you have said, then all power to you and enjoy. These are just suggestions to make things easier for people who don’t have that direction, nothing more.  Feel free to use all, some, or none of what I said. So long as you and your party are having a fun time and not hurting anyone then play however you like. 

P.s. - I like the creativity of your personal rule about not being able to conjure things you don’t know the working’s of or how it is made (like the acid). That would be fun to roleplay. I would caution you though. Many people don’t actually know how many common things work or how they are made. For example most people couldn’t tell you how a longsword is actually made or how silk rope is made. Those are skills that need to be learned. It’s like how today most people drive vehicles but very few people understand how an automatic transmission works. So don’t forget to have a reason your Wizard would know how these things work or are made. You could do that with easily enough with your backstory or through proficiencies or skills. Have a conversation with your DM about it beforehand. 

what do you y'all consider to be an object? can a fluid be considered an object? what about something that is normally a fluid but that has been temporarily frozen? can an single object comprised of multiple parts be a single object? what about a bag of ball bearings or a pile of powder? what about a chain? and similarly could minor conjuration reproduce any functionality of an item, for instance could an wizard who has previously used a poison such as essence of ether, that does not deal any damage but can make an person fall unconcious, produce essence of ether using minor conjuration? If it would not becuase of the single item clause, what if an wizard with a flair for alchemy mixed some of this powder with an solvent such as water, then froze the solvent, used minor conjuration to make such a cube and found an efficient way to then melt the ice distill the solvent from the powder in a couple of minutes?

From the DMG

an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.

An object is a singular item so liquids and powders do not quality. So you cannot make acid, water or such things. You could conjure a book, or a key, or a cup - but the cup would be empty.

Acid would be a discrete, inanimate item unless "being composed of molecules" is a problem which would lead to other issues.

However, acid functions through, essentially, mutual annihilation, so as soon as it starts eating through something the conjured acid would disappear.

It's a decent enough list, but for something trying to look at the "actual wording" there are a lot of assumptions being made about things that require DM interpretation. Let's look at each example:

Everyday objects? Of course. That's probably what was in mind, but it's not the limit of what can be made either. Good call-out.

A coil of rope? This one requires some interpretation. The rope itself is 50 feet long, but when coiled it fits within the size constraints. The RAW doesn't say one way or another in this case, so it's left up to the DM. A coil of rope with a grappling hook attached, however, would be two discrete objects, so this would not work by RAW unless the DM house rules it.

Containers of liquids? Not by RAW. The container is a discrete object, the liquid (even if a fluid is ruled by the DM to be a discrete object) is separate. You could make the container, but not the liquid.

Pouches, quivers, etc. with contents? Again, they are discrete objects. You could make a quiver OR one arrow, a bag OR one caltrop, etc.

A bag of coins? See above.

A book or spellbook? Sure, but whether it has anything in it is up to the DM because it's not covered by RAW one way or another.

A piece of the sun, black hole, etc.? Of course not, as you said. That would be ridiculous, even if those things were objects (which they aren't).

A key? Sure, that falls under the "everyday objects" category. Whether it opens a specific lock is not covered in the rules though, so it's left up to the DM.

Spell components? While RAW is unclear about the value of the conjured item, Jeremy Crawford has clarified that the intent is for the item to have no value - that is, it is not worth anything. So if you're trying to make a "pearl worth 100 gp" (for identify), you would not be able to.

Mitral and adamantine? I don't recall whether those two materials are specified as being magical, but if they are indeed nonmagical then there's no issue.

Just let them create the quiver of arrows.  All you do by limiting it is force the player to come up with some stupid game as to why its is one object.  I'm creating a quiver of arrows but each arrow is ever so slightly part of the quiver by one tiny little thread. You find some way that doesn't work they will find another word game to make it work. The same with the grappling hook and rope, its not a rope attached to a grappling hook its a rope that becomes a grappling hook. A lot of items are made of parts, if you limit to one item you take those away. A bike, sorry man that's got two wheels, a frame, a chain, way more than one item. a chair look a chair has nails, multiple pieces of wood...

And lets face it, its just not fun.  It wont take damage, it wont do damage past the first hit or point of damage depending on ow you read that, its obviously magical so you can't scam people with fake gold, it can't stand in for a material component of value apparently. It has to fit in a 3 foot box. Those are plenty of limits without having to make the player word game everything.

Quote from MyDudeicus >>

Just let them create the quiver of arrows.  All you do by limiting it is force the player to come up with some stupid game as to why its is one object.  I'm creating a quiver of arrows but each arrow is ever so slightly part of the quiver by one tiny little thread. You find some way that doesn't work they will find another word game to make it work. The same with the grappling hook and rope, its not a rope attached to a grappling hook its a rope that becomes a grappling hook. A lot of items are made of parts, if you limit to one item you take those away. A bike, sorry man that's got two wheels, a frame, a chain, way more than one item. a chair look a chair has nails, multiple pieces of wood...

 

And lets face it, its just not fun.  It wont take damage, it wont do damage past the first hit or point of damage depending on ow you read that, its obviously magical so you can't scam people with fake gold, it can't stand in for a material component of value apparently. It has to fit in a 3 foot box. Those are plenty of limits without having to make the player word game everything.

 We can argue about interpretation and DM fiat all we want, but the rules as written clearly state one object. Can a DM rule otherwise? Of course, but that's a house rule. In a guide, it's best to stick to the rules as written rather than the rules as you interpret them, or at least to be explicit about what the rules themselves allow and where you are adding your own ruling. That's my original point.

Yes but the definition of one object is not set in the rules. I'd call a bike one object.  But its a frame,  wheels, a chain, pedals etc. So someone else might say its 10- items. I'm fine seeing a flask filed with acid as 1 object, a quiver of arrows 1 object.

This is a great guide.  It is really too bad that “According to Jeremy Crawford” Conjuration Wizards cannot conjure spell components that have value - ie: a jewel encrusted bowl spell component for Heroes Feast.  Boy, good thing in Tasha’s they gave that ability to...  a Bard.