Stone Masters has developed its own SR (Stain resistance) rating system which grades the stones natural stain resistance on a scale ranging from 0 to 5.
Stones with a SR rating of 0 have very little natural resistance to staining, while stones with a rating of 5 are very resistance to staining.
All stones in our inventory are clearly labeled with a SR rating and this SR rating is based upon the stones stain resistance before the stone is treated with sealer. All of Stone Masters natural stone finished work is treated with 2 coats of high quality sealer.
What makes some stones a 0 and others as high as 5? The first and most significant factor that affects the slabs ability to resist stains is if the stone has been resin treated or not and the second most significant factor is the density of stone.
Resin treatments are either an acrylic or epoxy resin that is applied to the stones surface. In some cases this process is baked in a large curing oven and then the slab is face polished. In other cases it is simply applied with a roller or brush and left to air dry. This resin fills the pores, blemishes, fissures and other anomalies in the face of the stone. It also affords nearly perfect stain resistance. Not all resins are equal nor is the process in which they are applied. Those resin treatments that are simply brushed on are not as high a quality as those that are baked on and do not offer the same resistance to staining. Some resin treatments are vacuumed through the stone and some are even applied to both the front and back of the stone.
The density of the stone affects the stones natural stain resistance too. Very dense stones are less susceptible to staining and less absorptive than more porous stones. Dense stones treated with sealer have a low risk of staining whether they are resin treated or not, while more porous stones if not resin treated are venerable to staining even if they are treated with sealer.
Sealer is a penetrating mono molecular chemical coating that is extremely thin (almost not even measurable) except in microns, while resin is a hard durable and hard coating offering both scratch and stain resistance.
If you have any further questions feel free to call and ask we can help and show you real life examples of both resin and sealer to help you make the best decision for your counter-tops.