Kalkstein

Listed in our range under Limestone.

Portoro Extra

Portoro Extra is an Italian limestone with a deep black ground tone and high-contrast golden-yellow veins — the classic Portoro with dramatic depth. Polishable like a marble, used for bookmatch wall surfaces, bathrooms, fireplaces and prestigious interiors.

Kalkstein Italy

Available as: Slabs

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About Portoro Extra

Portoro Extra is the high-quality grade of the famous Italian Portoro family: a deep black ground tone through which high-contrast golden-yellow veins run — some fine and straight, others strong and with pronounced movement. The slab appearance is legendarily dramatic and has been used for centuries in prestigious buildings in Italy and across Europe: in palaces, churches, high-quality bathrooms, fireplace installations, bookmatch wall surfaces. It is precisely this iconic visual effect that makes the stone interesting for projects in which material and atmosphere are meant to go hand in hand.

In stock

Current availability from our warehouse.

1 slab in stock · plus 1 block

Thicknesses: 2 cm · Finishes: Polished · Available as: Slabs

Updated daily from our live stock.

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Technical data

Guide values for the stone type, taken from manufacturer and test reports. Natural stone is a natural product — individual batches and slabs can differ. For critical applications, request slab-specific test data.

Biegezugfestigkeit 10,2 MPa

Wasseraufnahme 0,09 %

Suitability by application

Suitable with limitations

Küche & Arbeitsplatten △ Limited

Care & fabrication

Portoro Extra is an acid-sensitive limestone. Wine, lemon juice, vinegar, cola, sanitary cleaners or descalers leave etch marks on the polished surface — visible as matt shadows or a loss of gloss. On the deep black ground such changes are visually particularly conspicuous, because the iconic depth effect suffers.

For all applications an impregnation on a silane or polysiloxane basis is mandatory. It prevents the penetration of water, oil and colouring agents and reduces the formation of stains — but it does not remove the acid sensitivity. On polished surfaces we recommend renewing the impregnation every 1-2 years.

Daily care is carried out with a pH-neutral natural stone cleaner and a soft microfibre cloth. On dark stone you should not work too wet and should take off residues cleanly and dry, so that no streaks arise. Avoid vinegar cleaners, cement veil removers, acidic sanitary cleaners and strongly alkaline agents.

Wine, coffee, oil, lemon and cosmetic products should not be left to act on polished surfaces for long. For heavily used kitchens Portoro Extra is only suitable to a limited extent — the iconic slab image is its value, not everyday robustness.

For permanently weathered external surfaces the material is not suitable.

Frequently asked questions

Is Portoro Extra suitable for the kitchen?

Only to a limited extent. As an acid-sensitive limestone it works only where the patina is accepted, the impregnation is consistent and acids are removed immediately. For carefree black kitchen worktops we recommend Toros Siyah or Nero Assoluto.

Which finishes are available for Portoro Extra?

The finishes available from stock are listed in the »Finishes« block on this page.

Where does Portoro Extra come from?

Portoro Extra comes from Italian deposits, classically from the region around Portovenere in Liguria. The name “Portoro” links Portovenere with the Italian word for gold (“oro”) — an allusion to the golden-yellow veins.

How do I clean and care for Portoro Extra?

Impregnation is mandatory. Daily care with a pH-neutral natural stone cleaner and a microfibre cloth. On dark stone, wipe dry afterwards. Avoid acidic cleaners, descalers and aggressive specialist chemicals.

Is Portoro Extra frost-resistant and suitable for outdoors?

For permanently weathered external surfaces the material is not suitable — as a limestone it reacts sensitively to de-icing salt and acidic precipitation. Indoors it is stable over the long term given appropriate care.

Portoro Extra or Portoro Brown — which suits better?

Both have similar care requirements. Portoro Extra appears more dramatic and more classically cool through its deep black with golden veins — the iconic presence. Portoro Brown brings a warm brown depth with it. For luxurious, prestigious rooms with a classic appearance, Portoro Extra is the better choice.

What does Portoro Extra cost?

The price depends on the batch, thickness, surface finish and fabrication — with natural stone there is no serious flat rate per square metre. Business customers see prices once their B2B account is activated; private customers receive a complete quote through a fabricator near them.