not quite. adamantine does cost 500 on top. mithril isnt quite as rare or tough as adamantine, so I'd say about half that.

Just looked this up via Sage advice.

Jeremy Crawford
@JeremyECrawford
Mithral armor is a magic item. It follows the rules for such items, including the text in antimagic field on magic items.

Jeremy Crawford
@JeremyECrawford
Mithral armor — its description specifies that it's medium or heavy armor.

Jeremy Crawford
@JeremyECrawford
Mithral armor doesn't weigh less than normal. Its description would say if it did.

Quote from Cryptworks >>

Just looked this up via Sage advice.

Jeremy Crawford
@JeremyECrawford
Mithral armor is a magic item. It follows the rules for such items, including the text in antimagic field on magic items.

Jeremy Crawford
@JeremyECrawford
Mithral armor — its description specifies that it's medium or heavy armor.

Jeremy Crawford
@JeremyECrawford
Mithral armor doesn't weigh less than normal. Its description would say if it did.

 And therein lies my main issue with D&D 5e. Mithril Armor has always weighed less than it's Steel or Adamantine counterparts. It has since it's inception. It's the main allure of Mithral! Being able to have heavy ass Full Plate (or, for those of you who like Dwarves, Dwarven Mountain Plate) and have it weigh half as much. I mean, for Ao's sake, it even says it's lighter in the description of the armor right there! 
"Mithral is a light, flexible metal."

Light. As in "does not weight all that much". And Flexible, for that matter. You could make a case that you should be able to add your DEX mod (Max of 2) to Mithral Plate cause it specifically says it's flexible.

Can anyone tell me why a Mithral Chain shirt has a AC of 13 plus a MAX 2 Dex modifer where studded armour has an AC of 12 and a plus 4 Dex modifier? 

Why is mithral worse on the dex modifer? 

When studded is equipped I get 16 AC, yet when I equip the MIthral I get AC 15 - both our DM  and I think it should be AC of 18.... Thanks in advance. 

Quote from Manpooshute >>

Can anyone tell me why a Mithral Chain shirt has a AC of 13 plus a MAX 2 Dex modifer where studded armour has an AC of 12 and a plus 4 Dex modifier? 

Why is mithral worse on the dex modifer? 

When studded is equipped I get 16 AC, yet when I equip the MIthral I get AC 15 - both our DM  and I think it should be AC of 18.... Thanks in advance. 

Chain shirt (mithral or no) is medium armor; studded leather is light armor. Medium armor Dex AC bonus is capped at 2. Light armor Dex AC bonus is uncapped. That is a basic 5e D&D rule. Mithral doesn't change that. The only advantage that a mithral chain shirt has over a regular chain shirt is that a mithral chain shirt can be worn under regular clothes.

What’s the point of a mithral chain shirt? 

Huh.. it doesn't lower the weight too? 

I see the previosu referende to forgotten realms but I don't know if that applies to 5E.

I guess I need to go dig up my books and check

Some one may have already asked this but: In a past edition Mithral made heavy armor medium armor.  Does it do the same in 5 edition?

The reason I ask is to see if there is a way around the barbarian rage not allowing heavy armor.  If Mithral full plate is considered medium armor then it would work.

Can mithral armor be upgraded? I got a mithral breastplate armor from last session and I was wondering if I can upgrade it to half-plate armor.

I landed here because I am DMing a game in which an orb made of mithral is being used for an imprisonment spell and I'm trying to figure out how big the thing is @ 500gp / hit die.

The amount of information on Mithral for 5e is thin.  If all Mithral does is remove the Dex disadvantage or Str requirement, then per pound it's not really all that valuable, in my opinion.

Let's say at *best* it would increase the cost by maybe around x3 to get rid of the penalty.  That would mean that Chain Mail @ 75 gp (normally) @ 55 lbs would be 225 gp.  (This number was derived from the masterwork rules of 3.5e).  I've seen recommendations of 800 gp for 5e mithral armor (regardless of type?), but that just doesn't seem worth it for the limited benefit.  But I'll still use that as a reference.

The crafting rules require the cost in materials to be half the market value.

A mithral chain mail suit @ 225 gp would mean that the materials would cost 112.5  gp.  That ends up being around 2.05 gp / lb of mithral.  If we apply the same principle to the spell component, a mithral orb to imprison a 1 HD creature would cost 250 gp in materials, which would be approximately 122 lbs per Hit Die of the target.  That's just nuts.

So let's say that mithral is overpriced at the other recommendation I have seen of 800 gp for mithral armor.  400 gp for materials = 7.27 gp / lb of mithral.  That still gets you to 34.39 lbs per Hit Die of the target.  So a mithral orb required to imprison a 13 HD Mummy Lord would weigh 447 lbs.  Umm.  No.

Also, the rule of thumb is that a gold coin is 1/3 of an ounce, which is roughly 50 coins per lb.  1 lb of gold = 50 gp, but 1 lb of Mithral is only 7.27 gp?  With a lb of silver = 5 GP, that means that Mithral is only *slightly* more expensive than silver and much cheaper than gold and also cheaper than Electrum!

If mithral is so valuable that you need an orb at 500 gp per Hit Die in order to cast a 9th level spell to imprison something, it *must* have more value than just dropping a disadvantage or strength requirement.

Either that, or the mithral orb is a misprint and it should be 50 gp per HD.  But that would mean it would only cost 650 gp to have a component that can imprison a Mummy Lord vs a 6500 gp component.  6500 gp component makes more sense.

If we go with the inspiration of Mithril from the Tolkein books, Mithral would be "worth ten times its weight in gold".  That would mean that one lb of mithral would be worth 500 gp and puts it at the same value as Platinum, another rare metal - but one more suitable for jewelry than for armor.

Therefore, in my world, I'm going to be using Mithral as follows:

1. Removes disadvantages for dex checks.
2. Removes strength requirements.
3. Medium and Light Armors get full Dex bonus and can be worn under normal clothing.
4. Heavy Armors get Dex bonus capped at +2
5. Half-weight.
6. +1 AC due to strength of the metal
7. Does not require proficiency in the armor to cast spells.

The generic rules for crafting is that half the cost goes towards the materials, the market value is double that which incorporates labor + markup for profit.

The nearest equivalent to mithral in actual chemistry is titanium when it comes to strength, malleability, density, and longevity.  In modern days, titanium is cheaper than platinum by a significant margin.  But before modern technology was able to mine and process it, it was much more rare in the past.

So @ 500 gp / lb, the material cost for a half-weight Mithral chain mail suit (27.5 lbs) would cost 13,750 gp.  Double that to determine market value of 27,500 gp (which incorporates labor + profit).  Truely a priceless item suitable as gifts for kings.

Using the same crafting rules, the spell component cost would be 250 gp / HD in materials, x2 to determine market value (labor + profit).  That would result in the following weights for Mithral Orbs:
1 HD imprisoning orb: .5 lbs
10 HD imprisoning orb: 5 lbs
13 HD imprisoning orb: 6.5 lbs
20 HD imprisoning orb: 10 lbs

Optional "mithral-steel alloy" rules:

Half the material costs for a mithral-steel alloy has the following benefits:

1. Removes disadvantages for dex checks.
2. Removes strength requirements.
3. Light Armors get full Dex bonus and can be worn under normal clothing.
4. Medium Armors get Dex bonus capped at +3.
5. Heavy Armors get Dex bonus capped at +1.
6. 75% weight

In addition, it requires a special unique proficiency to be able to work with pure mithral.  That proficiency would (obviously) be available to dwarves.  Possibly other races (elves most likely).  Those without it can only create the alloy version.

Any thoughts?

I just found it in one of my adventures. I believe it was chain mail. (If you are wondering, I am still kind of a noob, so I got this at second level.)

Would a wizard be able to use it?

Armor Proficiency. Anyone can put on a suit of armor or strap a shield to an arm. Only those proficient in the armor's use know how to wear it effectively, however. Your class gives you proficiency with certain types of armor. If you wear armor that you lack proficiency with, you have disadvantage on any ability check, saving throw, or attack roll that involves Strength or Dexterity, and you can't cast spells.

A wizard wouldn't be able to use mithral armor effectively unless they have the armor proficiency, UNLESS it is Elven Chain which specifically states that "you are considered proficient with this armor even if you lack proficiency with medium armor."

My dwarf forge cleric is excited to someday make this (Mithral plate armor) and a dwarven thrower! obviously this is only if the dm is willing to allow my middle aged mountain dwarf,who has been smithing for around 150 years to find the time and materials to make them.

One would think that Mithral would be silver or atleast silverish. Idk maybe it's my old phone but I wouldn't think it would blackish in color.

That's a generic placeholder image.

I realize this is an old comment. But just felt the need to point out what seems to me, to be a very misunderstood way to DM, imo. I know he regretted giving an overly powerful item to a low lvl player. But just countering it by matching monster stats, seems so cheap, and misunderstood to me. How is it any fun, to always have the part meet perfectly evenly matched monsters? If a player finds something amazing, chooses amazing abilities, or if a party just generally is able to punch above their weight, don't punish them by just fudging monster stats and increasing the difficulty. This isn't Diablo 3. Let them shine, let them punch above their weight. And then allow them to search out challenges that would normally be above their pay grade! 

Can't delete comment 

Quote from Japary >>

The removal of disadvantage to stealth is incredibly powerful for the heavier plate wearers. In my noob DM days, gave it to our paladin within the third session in a two part dungeon and didn’t realize the insane boon i’ve given him as now he can almost be as stealthy as the rest of the group and had 20 AC with a sword and board :( makes for a lot of modifying creature’s perception and to hit modifiers to be able to have a chance at hitting this silent moving tank of death. I would suggest maybe higher than 500 GP for at least the heavy armor and higher AC mediun armor or even holding off until higher levels of making it available as a drop or as a purchase in a store. That way they’ll be fighting creatures that actually have a chance to hit 20 AC on a regular basis.

 I realize this is an old comment. But just felt the need to point out what seems to me, to be a very misunderstood way to DM, imo. I know he regretted giving an overly powerful item to a low lvl player. But just countering it by matching monster stats, seems so cheap, and misunderstood to me. How is it any fun, to always have the part meet perfectly evenly matched monsters? If a player finds something amazing, chooses amazing abilities, or if a party just generally is able to punch above their weight, don't punish them by just fudging monster stats and increasing the difficulty. This isn't Diablo 3. Let them shine, let them punch above their weight. And then allow them to search out challenges that would normally be above their pay grade! 

i would take normal armor instead