PSA: Spirit of Harmony = $$$
This AH tip is from two expansions ago, but perhaps you also completely forgot it was a thing.
Do you know how in 7.1 there is a Blood of Sargeras trader? Well, there was one in Pandaria too. They are located in the Vale strongholds for your faction, out on the terrace. And, as it turns out, their exchange rates are very good:
Yes, a single Spirit of Harmony trades for 20 Ghost Iron Ore. Which are currently selling for 38g apiece on Auchindoun-US.
So, basically, if Spirit of Harmony are going for anything less than 760g each, then…
Now, what I will suggest is that you look at your own AH and not go too crazy with this sort of thing. Remember my Titansteel tip from Friday? I’ve sold two pieces, but the others have not yet sold. It’s entirely possible that they never sell at any price. Indeed, pretty much the sole purpose of any of these mats are to craft and sell mounts that have been out for 2+ expansions.
That said, I absolutely bought out all of the Spirits of Harmony below 250g and converted them to Trillium and White/Black Trillium Ore to post in the AH. Depending on sales, I might just toss in some Ghost Iron Ore as well. The profit margins are low considering that Starlight Rose is still ~75g a node, but I hate actively farming herbs and this breaks up the monotony.