Can I learn the formula for +1 weapon potency when I take magical crafting?

[Zamfield]

Is the formula for a rune considered a magical item for picking as one of your four free formulas when gaining the magical crafting feat?

[Themetricsystem]

That depends on if you consider a non-physical treasure to be considered an Item it seems.

The Feat itself indicates that you learn the Formula for four Magical Items and while the Runes are in the Treasure Chapter, they're not themselves items in the traditional sense.

Looks like something that could use some rewording there.

[Zamfield]

They are items in the rules sense as everything in that chapter is referred to as an item, even materials. The rune has an item stat block, with an item level and the magical trait. I don’t think we can say the feat is describing magical “things” flavored as “items”. It is clearly referring to the game rules in chapter 11 and any item found there that is common, has the magical, arcane, divine, occult, or primal trait and has an item level of 2 or less.

I was surprised to find people using layperson meaning on a game rule term of art

[Laran]

"The Price of a rune’s formula is the same as the Price of a
formula for an item of the same level; it can be acquired in
the same way as an item formula (described on page 293)." p581

Since runes are crafted via the same process as other items, I would think that you can get the formula for a +1 potency rune via magical crafting. The only ambiguity is that the above statement explicitly differentiates between runes and items so it is arguable that magical crafting is more limited