I've found one so far, no +. I was trying to get them for a few days and then I just killed an R3 marmot outside of Gridania and got one. They don't seem to drop off of anything particular in any specific area. Seems all means of obtaining items have a chance of dropping Deaspected Crystals. I'm going to hold onto mine as I'm sure they'll have a purpose down the line. They wouldn't put in an item with absolutely no purpose.