Finally got around to sifting a sample size of my volcanite. It's still winter here so I wasn't able to get outside and use my large sifting bins to do the whole bag like Wee did. I did a sample size of a little less than 1 gallon.
I used 2 screens sizes, 1/4" and 1/16". Here's what stayed on top of the 1/4" screen.
Here's what passed through the 1/4" screen and stayed on top of the 1/16" screen.
Here's what fell through the 1/16" screen.
Greater than 1/4" on the left compared to the 1/4" to 1/16" on the right.
I also tested the water retention and air rentention properties of the volcanite compared to the General Pumice Products.
Volcanite was 18% water retention and 39% air retention.
General Pumice Products was 23% water retention and 40% air retention.
Overall I'm pretty happy with the volcanite product particle size. Certainly the price is much better since I can source it locally and save on shipping.