Dropped from various monsters on corresponding day and weather. Weather has a higher drop rate than day tho.
Basicly anything that gives xp under weather effects or day of the week has a chance of droping these. They are used to upgrade all ice based Elemental path weapons from trail of the magains. This means added effect of Lowering magic att and boosting your own MAB with +INT
Prices at the min are sitting at 10k and you need 15 per weapon, expect the market to flood and the price to fall as more becomes freely known about how to get these.
For Blm looking to farm these for Varuna's +2, go to Uleguerand Range, gather some mobs and -aga them down. Doing this netted one per round for me with between 5-8 mobs per round.
**Near constant ice weather here**
It's currently Winter in Vana'diel (8th Feb 1113) so Ice weather is at it's most common. Get em while they're cold or be prepared to wait a few weeks for next winter...
