The Sealing Library · stone chemistry
Why the right sealer depends on your stone.
Not all stone is the same rock, and it does not take a sealer the same way. There are two mineral families under everything we seal, and knowing which one your stone belongs to is the difference between a coating that holds for years and one that never really bonded. Here is the honest version, family by family.
Two families under everything
Every stone is one of two kinds.
Ignore the trade names for a moment. Under the finish, natural stone is built from one of two mineral chemistries, and that chemistry is what decides how a coating grips it. Get the family right and the rest follows.
Family one · siliceous
Silica-based stone
Granite, quartzite, sandstone, slate and bluestone. These are built from quartz, feldspar and other silicate minerals, the same silicon and oxygen chemistry as glass. Their surface carries reactive sites that a mineral sol-gel can bond to directly. Broadly acid-resistant, and our most straightforward bond.
Family two · carbonate
Calcium-based stone
Limestone, travertine, marble and onyx. These are calcium carbonate, the same mineral as chalk and shell. A drop of acid will fizz on them. They anchor a coating by a different route, and porosity is the key variable: open, porous carbonate takes protection beautifully, while dense polished carbonate is the hard case. We will get to both, honestly.
Why this is the whole game: a sealer sold as one-size-fits-all is guessing at your stone. MineralProtect is the one and only next-generation sol-gel surface coating of its kind in Australia, and part of what makes it work is that it holds on both families, by two mechanisms, for the same honest result. New here? Start with how sealing works.
Family one · siliceous
Granite, quartzite and sandstone: a genuine bond.
Siliceous stone gives our chemistry exactly what it wants. The surface is rich in reactive silica sites, so as the sol-gel cures it forms a real chemical bond into the stone, the same class of Si-O-Si bond that holds glass and quartz together. This is not a film stuck on top. It is protection integrated into the surface itself.
It bonds in, on cure
The water-based sol wets into the surface, then cross-links and condenses onto the stone's own silica, forming covalent bonds continuous with the mineral. On granite, quartzite and sandstone that is a genuine chemical integration, not adhesion, so there is nothing sitting on top to peel or wash away.
Protection sits where the wear is
The coating cures as a dense inorganic network right at the surface, roughly 90 to 100 nanometres thin, where scrubbing, traffic, cleaners and oil actually land. That is the opposite of a pore sealer, which builds its protection millimetres down where none of that real-world use ever reaches.
Colourless, and still breathing
It changes only the surface energy, so water and oil stop gripping while the colour, finish and feel stay exactly as they were. Because it works at the surface rather than plugging the pores, the stone still breathes. Granite benchtops, sandstone paving and quartzite coping all take it superbly.
See it on your material: granite, or read how this holds up against real cleaning in surface resistance.
Family two · porous carbonate
Limestone and travertine: porous is a strength.
There is a myth that porous carbonate stone is too open, too soft or too thirsty to protect well. The opposite is true. On porous carbonate the coating anchors into the mineral and pore structure, and the more open the stone, the better that anchor holds. This is where a lot of Perth stone lives, and it is a sweet spot, not a compromise.
Anchor one
Pore interlock
The thin water-based sol wicks into the open pore network, then cures in place into a rigid inorganic network keyed into the pore mouths and grain contacts. Higher porosity gives it more to grip, so it anchors harder on the open stone that people wrongly assume is the weak case.
Anchor two
Its own network
The sol also cross-links to itself, building a dense silica-like network within the coating. That gives cohesion and strength that does not depend on the stone's chemistry at all, so the protection stands up on carbonate as well as it does on silica-rich stone.
Anchor three
Bonding to the silica in it
Natural Perth Tamala limestone is not pure carbonate. It carries a large fraction of quartz and feldspar, and our sol-gel grafts covalently onto that siliceous fraction, the same bond it forms on granite. Carbonate stone is rarely as pure as the textbook says.
Liquid limestone is the standout. Poured and reconstituted limestone is bound by a cement paste, so it behaves like concrete: our coating grafts a genuine bond onto that cement, then adds the pore interlock of the carbonate fines on top. That is why liquid limestone performs so strongly. And breathability matters most here. Coastal, salty, reticulated stone needs to keep releasing moisture, because a film that traps salt behind it lets that salt crystallise under the surface and flake it off. A colourless, breathable, surface-only coating is exactly what this stone wants.
The honest exception
Polished marble and onyx: where we say no.
Not every stone is a good fit, and we would rather tell you than sell you. Dense, polished, near non-porous carbonate is the one case that is genuinely off-vertical for us, and it is worth understanding why, because it is the exact opposite of the porous stone above.
No pores to anchor into
Polished marble and onyx are dense with almost no open porosity, so there is barely any pore structure for the coating to key into, and being nearly pure carbonate there is little silica to bond to either. The two anchors that make porous limestone a strength are both missing here. It is the hard case precisely because it is so dense and so pure.
Acid etches, and no sealer stops that
Carbonate dissolves in acid, so a splash of wine, lemon, vinegar or a common bathroom cleaner physically eats a dull mark into a polished marble surface. That is etching: material lost from the stone itself, not a stain sitting on top. No penetrating sealer prevents acid etching on stone. Anyone who tells you otherwise is overselling.
What we will say plainly: on a polished marble benchtop or an onyx feature we are not your best answer, and we will tell you so up front. Tumbled or honed marble, which is more open and more forgiving, is a different story and often worth assessing. If you are weighing up a polished marble surface, read the honest limits on polished marble first, and see the fuller picture in sealer types compared.
Match it to your material
Find your stone in the library.
Each guide grades how well we protect that exact material, and tells you straight where we are not the answer.
Siliceous
Granite
The straightforward bond: silica-rich, acid-resistant, and one of our strongest surfaces. Read the guide
Porous carbonate
Travertine
Open, characterful pool and patio stone where the porosity works in our favour. Read the guide
Porous carbonate
Limestone
Perth Tamala limestone in the coastal, salty, reticulated conditions it was made for. Read the guide
Cement-bound
Liquid limestone
Concrete-class anchoring plus pore interlock: one of the surfaces we protect best. Read the guide
The honest limit
Polished marble
Dense, acid-sensitive, off-vertical for us. Read exactly why before you decide. Read the guide
Everything else
The Sealing Library
Every common WA surface, by material, honestly graded. Search yours. Browse the library
Straight answers
Stone and sealer, answered.
Does the type of stone really change which sealer I need?
Yes. Stone falls into two mineral families, siliceous and carbonate, and they take a sealer differently. Siliceous stone like granite, quartzite and sandstone forms a genuine chemical bond with our sol-gel. Porous carbonate like limestone and travertine anchors into the mineral and pore structure instead. Both hold extremely well. What matters is matching the coating and the prep to the family, which is exactly what a certified applicator does.
Can you seal porous limestone and travertine, or is it too open?
The porosity is the advantage. On limestone, travertine and Perth Tamala limestone the water-based sol wicks into the open pore network and cures into a rigid inorganic network keyed into the pore mouths and grain contacts. More porosity means better anchoring, not worse. It stays breathable and colourless, which is exactly what porous coastal stone needs so trapped salt can still escape.
Is liquid limestone the same as natural limestone for sealing?
Chemically it behaves like concrete. Poured liquid limestone is bound by a cement paste, so our sol-gel grafts onto the surface the same way it does on concrete, a genuine bond, plus the pore interlock of the carbonate fines on top. It performs excellently and is one of our strongest surfaces.
Can you seal polished marble benchtops?
Polished marble and onyx are the honest exception. They are dense, near non-porous carbonate with almost no pore structure to anchor into and no acid resistance, so a household acid like lemon, wine or vinegar etches the surface. No penetrating sealer stops acid etching on stone. We will tell you that straight rather than sell you something that will not deliver. Tumbled or honed marble, which is more open, is a better candidate.
Will sealing change the colour of my stone?
No. MineralProtect is colourless and works by changing the surface energy, not by adding a film or an enhancer. Same colour, same finish, same feel. The only change is that water and oil no longer grip the surface. The enhancer and wet-look sealers many people are offered deliberately darken the stone, which ours does not.
Does a breathable sealer really matter on Perth stone?
On coastal and reticulated stone it matters a great deal. A film that seals the pores can trap salt and moisture behind it, and the salt crystallises under the surface and flakes it off. Because our coating protects at the surface and leaves the pores open, the stone can still breathe, so it does not drive that kind of damage the way a film can. More on that in sealing and maintenance.
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Know your stone. Seal it right.
Tell us what you have and we will match the right coating to the material, prepare it properly and register it under a 10-year guarantee. Where we are not the right answer, we will tell you straight.