beerthirty, I spoke to the guy at Ali's Organics. I gathered that the powdered Azomite was of good quality.
I have been using it all summer in some very poor performing areas of my garden. My asparagus bed was in terrible condition and it has improved greatly with the powered azomite watered around each asparagus plant.
What I like about the powered substance is that I can use it in a large watering can which has an extra holes in the sprinkler. Larger granules will be larged in the head or sprinkler of the watering can and I just take the head off and shake the granules on to one of the garden beds.