Highly mirror like polished marble finishes do look very appealing with sharpness, however it is very impractical as far as keeping it looking clean and spotless. Many of my clients have asked me why their suppliers or retailers do not inform them the careful cleaning instructions and maintenance required for these type of marble surfaces. In the case of acidic liquids such as cola, soft drinks, wines, vinegar, orange and lemon juices, they can have a detrimental effect on the polish on the marble hence leaving patches of dull spots, dull rings from wine glasses bottom, and in most extreme cases, very rough etched surfaces. Furthermore, many tiny scratches also a lot more visible from a mirror like marble polish finish.
To understand why polished marble is prone to acidic etching, we have to go back to factory polishing process, many people thought that the highly polished marble finish has been sealed with some form of gloss coating or similar, and also mistaken once is sealed it is going to be mirror like looking. However this is far from the truth, your highly polished marble finish is actually been ground and polished in many stages to a desired finish. The process would be as follows, once the slab is cut to size and sliced in the quarry/factory facilities, it is then brought to a polishing table where various machine polishing heads operating either manually or by computer to polish the slab to high polished finish.
The typical stages would be using 50 grit diamond pads/media, 100 grit, 200 grit, 400 grit, 800 grit, 1500 grit, 3000 grit and various polishing powders and so forth to close the pores and building up to a polish that looks amazing with colour, depth and clarity. To further protect the marble, we normally use a good quality penetrating sealer to seal off any micro pores, thereby producing a surface that preventing food stains, oily substances from penetrating the marble thus ease of cleaning and maintenance.
It is important to know that penetrating sealers that are used on these natural stone and marble surfaces are not coatings. Unlike coatings such as polyurethanes, acrylics and epoxies that form a plastic like barrier to seal off timber surfaces or waterproofing the substrate, these penetrating sealers are designed to reduce the capillaries of the stone thus providing water and oil repellent. However it is interesting to note that penetrating sealers will not stop surface etching from any acidic liquids, and any spills on polished marble and limestone will show up as whitish and dull spots.
There are many clients that have asked me why we cannot put a coating like polyurethane on a stone counter-top to stop the etching, my answer is many stones surface required vapour transmission to breath, also if we simply coated the smooth stone surfaces, we run the risks of these coatings of de-laminating over a short period of time from many adhesion problems. Furthermore the coating will be prone to scratching from everyday usage as well, and over time, the surface will look full of scratches, dull and patchy spots, and thereby it would be even a bigger task to remove all the coating from the marble surface to rectify the problem, making it not a viable practice at all.
I hope the above information is useful, and please contact us on 0425 266 839 for a no obligation onsite quotation for reviving your stone counter tops, bathroom vanity etc.