Not sure if that makes it good honey, but there’s that.
Do not do this ifs the honey is in a squeezable bear container. The honey will boil, make a hole in the bear and spray honey all over the inside of your microwave (the turntable helps this). This will make a huge mess and will make opening the microwave more challenging.
You can double-boil if you want, where the jar sits in a shallow water bath which you boil for 10--20 minutes or so to decrystalise the honey.
I thought: “Costco wouldn’t lie to me? Would they?”
Now I must go and find out.
We have had wildflower honey crystallize in the honeycomb when we left it in the garage over winter.
It can be decrystallized easily with gentle heat. I put our jars in a water bath in a pot and leave it over a low setting for about an hour until it is good. The water never gets over 125 or so, which should be fine.
There are some genuine honeys which rarely crystalize.
Afaik (as an amateur beekeeper), it is not a good indicator of anything in particular, there are even reports of adulterated honey crystallizing. This make sense, since honey and fake honey are both a supersaturated solution of sugars that will gladly crystalize if given an opportunity.