Be careful not to jump to typing too quick. I'm sure that that
was the day that she was waiting for. If you're trying to quote on earthsday I think she was doing earthsday synth for sonic belt, since she was going for success and not HQ and that generally is what is supported by the whole conditional crafting success/hq theory. Most of the speculation in these conditions (that's right, I admit that all it is is speculation) assumes that crafting on the day of the crystal enhances success but reduces hq and break, whereas crafting on the day opposite of the crystal enhances hq but also breaks, and lowers success.
She was going for the HQ on this one, thus lightningsday for an earth crystal synth. I'm surprised that this evaded your attention, but now ya know, eh skeetaru? *skeet skeet skeet*