I've got two yards sitting in a pile. I sift it out as I need it. I have shipped out three gal. boxes of 1/4" for $40. I made about five bucks a gal. and the rest is shipping.
The pile is everything from sand to big half inch chunk. I use it all. The fines are the best thing for cuttings. I can make it up any size, all one size or all mixed together.
I'm not a big production, just a guy with access, but I will drop everything and get you your pumice post haste. Takes longer to get to the post office than it does to sift and box it up. By the way, I pay $40 a yard, so if I can ship out a couple of boxes I've paid for the whole pile, and you've got your pumice. I am not in the business, I only make this offer to my B- nutty friends.