Why do we need a glass mortar and pestle bowl? Glass mortar and pestle bowl is used to crush, grind, and mix medicine powders, seeds and herbs mixtures. It is an effective tool to reduce the particle size and perfect to crushing meds. Product features: Glass mortar and pestle bowl is made of heavy and strong glass material. Compare with the stone mortar, the glass surface is smoother so medicine powders don't usually adhere to the sides. Glass material is crystal clear to ensure its maximum visibility, easy to see the particle size. Tips on how to grind properly with the mortar and pestle bowl: When grinding, please push down on it and rotate the grinding head around, don’t crack at it, otherwise it might end up sending solid particles flying across the pharmacy or science lab. Not recommended for using with soft, moisty or sticky ingredients.