This is a very high quality perlite, yet the description is inaccurate. I have bought a couple of bags from PVO. All bags included about 20% fine to micronized matter. The manufacturer purposely includes this to increase it's water holding capacity, which I learned by reading other websites. I sift all my NorCal perlite through a spaghetti strainer while wearing a very high quality dust mask. This is very time consuming, and that's why it gets only 3 stars. There is a popular Giant Perlite #4 manufactured by a company in Nevada that should be sold here, but it's not at the time I'm writing this.