It's most likely fine quality, but if you want the himalayan salt that has been researched in the book Water and Salt, you need to get it from a specific area in Pakistan, not Tibet which is mentioned in your link. This salt is pink in color.
Evidently, all salt is not equal. I have been using the authentic with great results.
If you are using it for sole drinking therapy, even at the high prices, it lasts for 6 months or so....just 2 lbs. But if you are using it for bathing, it can get pricey.