Are the Heartstones the Reachmen are using in the Horns of the Reach DLC the same as the ones we saw in the Dragonborn DLC for Skyrim?
Which is to say, are the Heart Stones that got spat out of Red Mountain made of Nirncrux, just not known by that name since the substance didn't get a name until Craglorn?
(Yes, I know officially it only comes from Craglorn. It comes out of the earth, so I see no reason a vein of the stuff couldn't pass through Red Mountain and Craglorn is just the only place it comes out near the surface where people can find it.)
PAWS (Positively Against Wrip-off Stuff) - Say No to Crown Crates!
A useful explanation for how RNG works