#peppermint schnapps

My wife Te and I -- infrequent drinkers, to put it mildly -- have had that 50ml 'single serving' nips bottle for, uh, an unknown number of years, breaking it out when one or both of us wanted minty hoy chocolate and not at all otherwise. i used about the same amount that's still in the bottle to doctor my chocolate milkshake tonight.

What you are looking at, friends and strangers, is what I am calling pepprecipitousness. As in, something precipitated out of the peppermint solution, like in chemistry class, only delicious in this case.

Prior to today, I had had no idea that anything could precipitate out of schnapps at room temperature. I'm curious:

what conditions led to the crystals growing

what the chemical composition of the crystals is

what that means about the remaining liquid

whether that means I oughtn't to've drunk even a little

Would someone sciencier than me kindly opine as to the provenance (and safe-to-drink-ance) of these crystals?

Lastly here is the front of the label, in case that changes anything: