stone of the month january 2020

texts and images from: Natural Stones Worldwide ONLINE

Portoro Nero/Giallo
information A black limestone ( fault breccia ) of the Jurassic period (Lias), with large, yellow streaked veins, Italian "nero/giallo" = black/yellow.
Technical and physical characteristics: Bulk density: 2,71 kg/dm³, bending strength: 10,2 N/mm², compression breaking load: 157 - 182 N/mm², water absorption: 0,03 vol.-%, abrasion resistance: 1,8 mm (according to Amsler), not frost resistant, polish constant only inside.
Uses: Ornamental stone inside and for decorative craft objects.

This stone internationally may be nominated as a marble. For the US- and Chinese market this is correct according to ASTM C 119 resp. GB/T 17670. But in the area of application of the European Standard (EN) this stone must be nominated as limestone because the EN 12440 demands a scientific terminology for the denomination of natural stones, determined with a petrografic examination according to EN 12407 and 4.2 of prEN 12670. In case of doubt please ask your supplier.

origin Italy (Portovenere, Isola Palmaria/Provincia di La Spezia/Riviera/Apennines/Liguria)
synonyms Portoro Extra
suppliers E U R O P E
"Portoro Extra", quarry: Caro & Colombi SPA, I-54033 Carrara (MS)/Italy; email:; web:;  

"Portoro Extra", blocks, slabs, cut-to-size: Paiotti Group S.r.l., I-55045 Pietrasanta (LU)/Italy; email: info@paiotti.i; web:;

"Portoro Extra", blocks, slabs: Quema S.r.l., I-55045 Pietrasanta (LU)/Italy; email:; web:;

"Portoro Extra", slabs, cut-to-size: Antolini Luigi & C. S.P.A., I-37010 Sega di Cavaion (VR)/Italy; email:; web:;

"Portoro Extra", slabs, tiles, cut-to-size: Biasi Emilio & Figli S.r.l., I-37010 Sega di Cavaion Veronese/Italy; email:; web:;

"Portoro Extra", slabs, tiles, cut-to-size: Rossittis GmbH, D-59439 Holzwickede/Germany; email:; web:;

N O R T H - A M E R I C A
"Portoro Extra", slabs: Pietra Fina Inc., USA-San Francisco, CA 94545; email:; web:;

Portoro Nero/Giallo, sample slab

Portoro Nero/Giallo, sample slab

Portoro Nero/Giallo, macro

Portoro Nero/Giallo, macro

Portoro Nero/Giallo, macro
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