The "completely depleted" stuff is marketing fluff. Norton owns the original Lily White deposits and just doesn't mine them any more. Much more money in selling India and Crystolon, etc. They did do a fresh limited run of Lily White around 10 or more years ago. Someday maybe they'll do another one.
The original Washita stones were fast cutting and still fairly fine. You can pretty quickly sharpen up a chisel on one and it will still shave arm hair cleanly. Pretty much came into popularity back in the day because it was a quick, one stone solution for carpenters and such. They were available in differing hardness levels. The Lily White were selected to basically be the most uniform in appearance and grit throughout the stone. #1, #2 etc. would have increasing levels of uneven grit or color variation. The more modern ones they call Washita that I've tried from Dan's and elsewhere are much lower in hardness and more porous. They don't hold shape as well as the old stones, so in other words they gouge easier. I've got around 10 or 15 of the old Norton and Pike stones in my collection.
The only drawback to these and other Arks is that they're composed of pretty much pure silica, so they aren't of much use for any steel with any higher percentage of the harder carbides.
