Perlite and Vermiculite are sold in 4 Grades / Sizes…
Grade 1 - Super Fine
Grade 2 - Fine
Grade 3 - Medium
Grade 4 - Course
Personally, we would stay away from Grade 1 / Super Fine since it’s like working with dust. Grades 2, 3 & 4 are good to work with (grades 2 and 3 are preferred).