Portor is a very rare marble quarried in Italy and in Corsica. It is sometimes found in France, but very sparingly. It is known for its dark black color scattered with yellow grooves. Sometimes these grooves are grey, the marble is then know as Portagent.
The most beautiful Portor is dark black with deep yellow veins, like golden flames. Its name most likely comes from the town of Porto Venere on the Genoese coast where Louis XIV exploited quarries to decorate Versailles Palace. Much used in the 17th, 18th and up until the 20th century with the Art Deco style, for beautiful furniture, works of art and fireplace mantels.
In his dictionary on business and industry, Blanqui describes Portor marble as the following, “the background of this marble is black and the veins are golden yellow, giving it its name Portor (golden door). It must be considered as one of the most elegant marbles, yet it is only really sought after once its quality leaves nothing to be desired. Portor comes from the golfe de la Spezia (Golfe de Gênes)”.
J. Dubarry de Lasalle, Identifying marbles, Ed. H. Vial, Dourdan, 2000
J. Dubarry de Lasalle, Using marbles, Ed. H. Vial, Dourdan, 2005
P. Julien, Marbles, From quarries to palaces, ed. Le Bec en l'air, Manosque, 2006
Marmi antichi, collective work, ed. De Luca, Rome, 1998