thanks. I`m new to this, i did not rlly know how all of this works.

There is this homebrew...

Adamanthral is an alloy of adamantine and mithral, making it both light and flexible, yet strong and durable.

It is listed as rare in its base form, which sounds about right. Two uncommon base materials alloyed together should be at least one step up the ladder of scarcity.

One word Craftmanship...

Quote from Dartagnan_Galochio >>

Quote from Punk_Platypus >>

how much would a solid adamantine armer cost and what is its weight 

 

 Cost: I'd say add a bit onto the higher between the mundane armor cost and the Uncommon Magic Item cost.

Weight: As if normal mundane armor.

 Full plate is 65 lbs of steel, adamantine is twice that weight and mithral is half. One lb of mithral is 50 gp in lvl 6 of DMM, adamantine is 100gp in dragon heist. So material cost of pure mithral plate is 32.5*50 =1625 and 6500 for adamantine. I add the regular item cost for say splint armor, but mithral could take a jeweler to craft, and adamantine needs an extreme heat source like Sundabar's volcano or Gauntlegrimm.

Does this anti crit work on spell attack? 

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Quote from Legengerry >>

If a crit becomes a normal hit does that mean it can fail at your AC, or is it still an auto-hit just with normal damage?

 Still an auto-hit

Quote from Heinzeyy >>

Does this anti crit work on spell attack? 

 Yes

i hope your joking, lol no it has a chart for every armor type above

Seeing as adamantine has an ac of 23, adding this with an eefreeti chain or armor of resistance would be amazing armor for a BBEG.

(And I do know that this armor doesn't have adamantine's ac of 23 but it really just depends on how you like the rules to be on this armor)

While you're wearing it, any critical hit against you becomes a normal hit.

This does not claim Adamantine is a metal like Mithral, is it a metal or a hard rock that can be cut into armor? Druid asking.

Spontaneous homebrew, 

"Adamantine Knuckles", while holding one of those Knuckledusters, your unarmed attacks score a critical hit on a roll of 19 or 20.

They say Adaminite armour is the hardest thing they've every seen. Clearly, they haven't seen me.

Suspended animation/10

Sorry. All the armour types adamantine can be added to are metal (medium or heavy -hide).

I found an issue where an Artificer cannot infuse adamantine armor, even though it is not considered magical by definition. It seems this is true for any item that has a rarity tag (cannot be infused), regardless of magical properties. 

It's an uncommon magic item. It is magical by definition. The assumption I guess that's implied is that the adamantine is just metal but has a magical property to prevent crits.

I see what you mean. Also, I just found this X post by Jeremy Crawford confirming this. Thanks!

Quote from Black_Chocobo >>

Quote from Dartagnan_Galochio >>

Quote from Punk_Platypus >>

how much would a solid adamantine armer cost and what is its weight 

 

 Cost: I'd say add a bit onto the higher between the mundane armor cost and the Uncommon Magic Item cost.

Weight: As if normal mundane armor.

 Full plate is 65 lbs of steel, adamantine is twice that weight and mithral is half. One lb of mithral is 50 gp in lvl 6 of DMM, adamantine is 100gp in dragon heist. So material cost of pure mithral plate is 32.5*50 =1625 and 6500 for adamantine. I add the regular item cost for say splint armor, but mithral could take a jeweler to craft, and adamantine needs an extreme heat source like Sundabar's volcano or Gauntlegrimm.

 If mithral is half the weight and 50 gold, totaling 32.5*50 = 1625, then adamantine being twice the weight and being 100 gold, totaling 130*100 = 13000. Even if you argued that you'd need half as much adamantine to equal the same weight, it'd still be 32.5*100 = 3250. Makes no sense that you say that 1lb of mithril would only need half the material and 1lb of adamantine being twice that weight wouldn't need twice or half. So either way, your math needs work.

beanz