Yes, it is a hard <"Cretaceous age limestone"> with lots of shell fragments.Does anyone know if Kentish Ragstone is safe for aquarium use. I think it’s a type of limestone which makes me wary. There’s a nice big pile near me trying to save the pennies
How hard is your water? If your water is already hard, then I shouldn’t worry too much about using it.
As the other have said, if you have hard water, and don't tend to inject CO2, it won't dissolve and <"make your water any harder">.if it is possible to make Kent water any harder!
Apparently usually interbedded <"with"Hassock", a softer sandy rock">, in the Hythe formation.bashing wooden pegs into the ground in a ragstone quarry it is more like a sandstone