Petalcryst can be found in Hoarfrost Reach During an "Upsurge: frozen foliage" in the lower left of area 8 when looking at the map, in a cave, near the usual Frozen Foliage icons you normally see. There are two entrances to the cave. The top entrance is located at the north entrance of area 2, when you get to the 3 way intersection from area 2, continue forward into the crawlspace into the cave. Go down the slope to your left and as you descend the next slope, the foliage should be right there sparkling and ready to gather. If you reach the Baitbug, youve gone too far. The second entrance is located along the downwards slope into Area 8 from Area 4 (the area with the (Collapsed Snowfield) Environmental trap). There are two small holes to crawl through along the left wall, opposite from the snow herb to the right (there may be a mining outcrop there dividing the two holes, so look for that). If youve gone past either the outcrop or the snow herb, youve gone too far. Crawl Through the hole and go right. Pass the plants, the 1st gathering point, and the honey and go to the slope leading up. You should see a baitbug a bonepile and frozen foliage at the base. head up the slope once and turn left and it should be there sparkling waiting for pickup. I hope this unnecessarily over-detailed description helps someone.