Panacea Silica Gel Flower Drying Crystals capture the transient beauty of your fresh flowers. 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 its time to re-heat your crystals. This package contains 1-1/2 lbs. of silica flower-drying crystals and instructions. Conforms to ASTM D4236. It is an imported product.