What technically is natural stone?
According to the CLR Pro label, one of the “Do not use on” surfaces is natural stone. Texas and the southwest in general use concrete and stones mixed together and the mixture is applied to the outside of commercial buildings in a similar fashion to stucco. Natural stone is anything porous/soft such as limestone, terrazzo, marble, slate, some granite…although granite is a harder stone meaning, it’s not as soft or porous as the others mentioned, we have to be careful with this one. Only when granite is sealed, it’s okay, although Rosemary has okay’d for me for cemetery use in the past. The dilution was cut 1 part to 8 parts water, and always test before using fully. A couple of customers that used CLR on non-sealed granite said it worked fine without clouding the granite, which happens on marble since CLR is too acidic for the soft stone (or having a low pH of about a 2).
