NERO PORTORO

Pitch black is in fact embellished with a web of gold veins

Marble

Portoro, or Portovenere Marble, is a prized variety of black limestone from the western Gulf of La Spezia, but also from the eastern Gulf of Monte Caprione (Cave dei Branzi, Cave dei Merlon). Its exquisite and highly decorative appearance meant that it was once widely used as an ornamental stone and marketed as marble, making it suitable for artistic and prestigious creations such as vases, columns, pilaster strips, balustrades, interiors of historic churches and stately homes, cladding, flooring, and furniture tops. Its color is intense and brilliant black with golden or mustard yellow veins, more rarely orange. Geologically, it is a Liassic limestone with carbonate veins of limonite, formed in a calm, deep, poorly oxygenated marine environment rich in organic matter. The black color is due to its rich organic matter content, while the golden streaks are due to the partial dolomitization of the oxidized organic matter. In addition to the color, the microcrystalline structure resulting from dynamometamorphic processes also contributes to the quality of this marble, which can be classified as a compact, crystalline saccharoid.