Water marking on silica agglomerates

The technology of using high silica in resin to create a stone like surface is still relatively new. Brands such as Silestone, Caesarstone and Quarella among others all use the technology to varying degrees. It makes a durable material particularly suited to use on bench tops. In fact I have one myself and I can testify to its performance and durability. However over the last 7-8 years I have come across several jobs where water penetration has created problems with this type of material and in each case the result was the same. These are representative of all the problems I have inspected. In each case the stone has discoloured (a bleaching effect) primarily along the grout joint. No manufacturer or importer of the technology has been able to shed any light on the issue other than to say it has happened from time to time. In some cases the discoloration has been reversed by applying Poultice and Heavy Duty Tile and Grout Cleaner, however it returns as long as it still exposed to water. Without proper testing I cannot make any concrete conclusions other than this type of technology does not always like prolonged exposure to water. Going through the cut side of the stone where absorption is higher seems to be a common thread hence the route through the grout joint. In my opinion it is more than likely to be something to do with the resin binder and how it has cured however without more testing I can only recommend to TREAD WITH CAUTION.