As a buyer, I was very impressed with a set up I saw back in September. There is a photo of the table on my blog - lemme see....

there are a few more shots here:
http://doxallodesigns.blogspot.com/2010/09/picture-day.htmlSo it was trays, but they were divided, one cab to a compartment - probably made it easy for them to keep track of their stones! Each stone was on a card, each card labelled on the front with the stone ID. As a buyer - REALLY nice. :)
They did have some slabs off to one side - they were in plastic tubs in water - worked for me. I bought my very first slabs there! Wahooooooooooooo!
