How to Clean Marble and Granite-Aggregate Floors — Mistakes to Avoid, Safe Methods

Marble and terrazzo: one golden rule

Marble — and terrazzo, which is crushed marble bound in cement or resin — has one rule that needs to be known before any other: no acids. The reason is chemical: marble is essentially pure calcium carbonate (CaCO₃), and any acid dissolves it in 30–60 seconds, leaving an opaque mark that isn't a surface stain but a micro-removal of material. That's why instructions for a marble surface always start with the list of forbidden products and only afterwards move to what to use.

Why vinegar ruins marble: the chemistry explained

Marble is 95–99% calcite (CaCO₃) — the same mineral as the limescale we try to remove with vinegar elsewhere. When an acid touches marble, an elementary reaction kicks in that anyone has seen in high-school chemistry:

CaCO₃ + 2 H⁺ → Ca²⁺ + H₂O + CO₂

The marble literally dissolves. In under a minute a matte mark appears — the English call it etching — which isn't a surface stain but a small chemical crater. The only solution is professional re-polishing: no household product recovers it.

Weekly ordinary cleaning

Stains and marks: what to do as soon as they happen

Water stains and droplet marks

Polished marble develops water stains from slow evaporation, especially in the bathroom and kitchen where moisture is constant. The fix is a gentle paste of baking soda and water at toothpaste consistency, applied with a soft cloth in light circular motions. Rinse immediately with clean water and dry straight away: baking soda is mildly alkaline so safe for marble, but it's also slightly abrasive, so don't scrub hard.

Organic stains (wine, coffee, oil)

Here the deciding factor is time. Blot — don't rub — within thirty seconds: absorbent paper to lift the surface liquid first, then water and neutral soap on a barely-wet cloth with gentle friction, then full drying. For somewhat more persistent marks, the same baking-soda paste from the previous paragraph does the work.

Dark stains set in over time

These are the marks you can see but no household treatment shifts: they've had time to absorb into the pores of the marble. The only effective solution is professional poultice treatment, specific chemical packs that draw the contaminant out from below. It's a targeted intervention, not a routine treatment.

Maintaining shine between professional polishings

Between one professional polish and the next, shine is maintained with three different tools depending on the case. A marble-specific wax (never the parquet kind) goes on every 6–12 months and gives a veiled effect that protects the surface and refreshes its look. Linseed oil works only on rustic terrazzo, never on polished marble. For small surfaces you can attempt DIY crystallisation with products like Bellinzoni in CHF 25–40 bottles: for a small console or a single step it's feasible, but on a whole floor a professional is the right call because uniformity is hard to achieve.

When to call a professional

Terrazzo: marble's cousin

Terrazzo is made of marble (and other stone) chips bound in cement or resin, then ground flat. The same rule as marble applies: no acids, because the calcite in the chips reacts exactly like calcite in solid marble — no room for ambiguity. Neutral or Marseille soap, same procedure as ordinary cleaning. The important difference is that cement-based terrazzo is porous and absorbs stains more easily than polished marble; that's why water-repellent treatment — less optional than on marble — makes a tangible difference to longevity.

Honest comparison: DIY vs. professional

Prevention: the habits that avoid trouble

The best protection for marble isn't the right product but the right habit. Blot immediately every spilled liquid is the universal rule, and it applies even to the water from plant watering, which leaves its mark with prolonged contact. Doormats at the entrance reduce the sand and scratches it brings into the rooms. No vases without coasters on marble worktops, and watch out for stainless-steel cleaning products near a marble sink — some contain acids and a single drop of overspray is enough. Last, the rule that seems obvious but gets skipped: no open bottles of vinegar or lemon left on the marble worktop. An accidental fall in the few minutes you're not in the kitchen is one of the most common ways people discover etching.