I'm writing this primarily because a good deal more information is available for the Lands of Porphyra campaign setting and that can change perspective on the value of this work. Godmetals of Porphyra is a short work, and underappreciated. The eponymous godmetals are seven in number, each with different uses. Not all of them are designed to be in the hands of player characters under normal circumstances. Hellstone and Mawine both read like they were designed with evil rogues and assassins in mind. Both have properties to them that a clever DM could apply to traps. Although this book was created in response to Paizo's Skymetals being Product Identity, I feel that an update should be done to make the Godmetals concept more Porphyran. There are 27 deities in Lands of Porphyra, and while some of them ascended during the Calling, in the lore that era took place almost 1,000 years ago. We have 7 godmetals, maybe someday we could have 27. It would be more interesting, though, if the idea were instead expanded beyond the existing special ores and stones to include other divine materials used in crafting. *****

The seven Godmetals are a reskin of the seven skymetals first published in Pathfinder Adventure Path #61, and reprinted in the Technology Guide. As a result, all the rules for them are now available for free on the PRD.

Yes, this was published in 2013, before this was the case. And the PDF is still pay-what-you-want. So it seems unfair to rate this too low. Still, it would be nice if PDG updated the product description so buyers/downloaders knew what they were getting.

So is it worth getting for the fluff? Each metal (including adamantine) has 2 or 3 sentences explaining its presence in the world of Porphyra, what virtues & schools of magic it tends to be associated with, which god brought it to the world, etc. If you dislike the "super-science" flavour of the Technology Guide, but want to port some of its rules back to a more traditional setting, reading through this may spark some ideas.

This is a fair-sized PDF document offered free of charge. I do not remember if "Porphyra" refers to a certain fantasy universe. Without spoiling the experience, the "Godmetals" of the title are drawn from divine essences. This seemed intriguing, but I became disillusioned. The names (one was related to "stone", therefore not a "metal" in my mind) and characteristics (proving player character tactical combat benefits) didn't fit with the kind of adventures and stories I would like to create. I attempted to use write a small list of the names/characteristics to spur my own creativity, but stopped because this simply wasn't useful to me in any fashion. However, it is provided free of charge.