the winter 2012 residents of the Wassaic Project are obsessed with these beautiful blue rocks. they are probably industrial slag, which is less than a beautiful idea, but they are beautiful products.
We used them as the centerpiece/main visual for the Passover Seder. Ashley and I had to take them to an in-house Rock Spa to get them ready for their big performance.
According to Google searching, leftovers from Iron Ore processing. Was there an IronWorks in the area?
http://www.wassaicproject.org/about-3mission/history/
Gridley Ironworks
THANK YOU, RESEARCH & FACT-CHECKING INTERN!