PANACEA-Flower Drying Crystals. Capture the transient beauty of your fresh flowers with these flower-drying crystals. These crystals will dry your flowers in just a few days or in minutes if you use the microwave method. Blue indicator crystals let you know when it's time to re-heat your crystals. This package contains 1-1/2lbs of silica flower-drying crystals and instructions. Conforms to ASTM D4236. Imported.