In my current D&D campaign, I'm an artificer. Part of our role playing is me inventing numerous weak magical trinkets for my allies. I like to write the item descriptions for these in a WotC-style language to make them feel more real.

Currently I'm looking for a vanilla mineral that generates constant heat. This feels like something that would have been described at some point in the sprawling Dungeons and Dragons lore, but my Googling's turning up nothing.

What mineral from any D&D published lore is described as generating heat?

As an example, I'm currently substituting "two small pieces of infernal jadeite, pulled from the elemental plane of fire," which I made up. There aren't really any limitations on this; the more exotic this mineral the better, and the method by which I need to acquire this mineral doesn't really matter. The only consideration is that ideally it would be quite small.

  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – mxyzplk
    Aug 31, 2018 at 12:22

2 Answers 2


There's (potentially) a lore-backed mineral that generates heat right in the 5e PHB.

The Trinkets table, p. 151 of the Fifth Edition PHB, contains a reference to the following:

A shard of obsidian that always feels warm to the touch

Because trinkets are supposed to be mysterious oddities and potential adventure hooks, there is no narrative explanation provided for why the shard of obsidian generates heat. The very appearance of the shard on the Trinkets table arguably implies that it is special in some way, and that its heat-generating quality is unusual. (Ordinary, real-world obsidian doesn't meaningfully generate heat, after all.) It could be, for example, that something has been done to this specific shard to cause it to generate heat. But it could just as easily be that all obsidian in your game's setting generates heat -- although that might diminish the uniqueness of this particular trinket. For that matter, the fact that it "feels warm" could arise from something other than actual warmth -- an illusory feeling in the mind of the person touching the shard, for example.

In any event, if you're looking for precedent, there it is.

There are other (potential) options from the 3e Forgotten Realms supplement Magic of Faerûn.

MoF includes numerous "special materials" that can be used to craft items. A couple of those materials, if used to create weapons, provide bonus fire damage: fever iron, a magic metal from volcanic craters (p. 178), and hizagkuur, a magic metal from the Underdark (p. 179).

Curiously, neither entry explicitly says the materials feel warm or otherwise generate heat in any way except dealing fire damage. Nevertheless, it stands to reason that a substance that deals fire damage would have to generate heat somehow -- on impact at the very least.

  • 6
    \$\begingroup\$ It's probably worth pointing out that the description implies that feeling warm to the touch is an exceptional property for obsidian to have. That is, there's nothing about the obsidian itself that should cause it to (appear to) produce heat. So on the one hand, this example doesn't supply a type of heat-producing mineral. But on the other hand, it does give a perfect example of a minor (presumably) magical trinket that produces a bit of heat, which sounds like a great fit for what the asker is looking for. \$\endgroup\$ Aug 30, 2018 at 14:16
  • \$\begingroup\$ @RyanThompson See edit. Does that adequately address your point? \$\endgroup\$
    – screamline
    Sep 4, 2018 at 21:21
  • \$\begingroup\$ Yes, I'd say so. To be clear, my comment wasn't a complaint, but rather pointing out that while it didn't technically answer the question as asked (a type of heat-generating mineral), it might instead address the underlying motivation for asking the question (a lore justification for a heat-generating rock). I didn't mean to imply that this was necessarily good or bad, just worth nothing the distinction. (For the record, I upvoted your answer.) \$\endgroup\$ Sep 4, 2018 at 21:58

Heatstone, in Pathfinder, right in the adventuring gear page:

Alchemically treated to enhance their natural heat-generating properties, these round or ovoid stones of volcanic glass provide enough heat to keep chambers warm in the coldest winter. One heatstone keeps a 20-foot-square area comfortably warm even in extreme cold (below –20° F), or a 40-foot-square area in severe cold (between –20° F and 0° F). A single heatstone is activated by striking it against any hard surface, after which point it continues to provide heat for 24 hours. An active heatstone does not give off enough heat to cook food or cause damage.

Not exactly "a mineral" but really alchemy seems to be right up your alley!

For those who aren't aware; Pathfinder "extends and modifies the Revised 3rd edition Dungeons & Dragons (D&D) game rules published by Wizards of the Coast under the Open Game License."

As per comment by @ShadowKras "The Pathfinder wikia has more lore information about this item, which is taken directly from the Inner Sea World Guide."

  • \$\begingroup\$ Comments are not for extended discussion; this conversation tending toward the PF/D&D relationship has been moved to chat. \$\endgroup\$
    – nitsua60
    Aug 30, 2018 at 17:56
  • \$\begingroup\$ Since it says the alchemy only enhances the natural effects of the "volcano glass," I would argue that this counts as a mineral, not just alchemy. Also, note that the obsidian mentioned in 5th edition is a form of volcanic glass. So you have other D&D sources you could link this to if peolple are concerned Pathfinder doesn't count on its own. (All of this is info I think could be added to the answer) \$\endgroup\$
    – trlkly
    Aug 30, 2018 at 21:49

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