Nero Portoro Limestone From Italy
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Description: Nero Portoro Limestone is a black limestone (fault breccia) of the Jurassic period (Lias) with intensive yellow stylolitic veins and partly white, streaked veins. This stone internationally may be nominated as a marble but in the area of application of the European Standard this stone must be nominated as limestone. The veining and colour varies considerably and a small sample of Nero Portoro Limestone may not be representative of the whole slab therefore swatch samples must be approved for large projects to ensure that the blocks are all extracted from the same quarry face for matching purposes. During the polishing process a clear epoxy resin filler may be used to fill any micro fissures or tiny pitting however this does not affect the integrity of the stone, it merely provides an even smoother surface finish. Nero Portoro limestone is ideal for both interior and exterior use however it is not frost resistant and the polish is only constant inside.
The use of polished Nero Portoro limestone is not recommended for flooring tiles owing to high breakage rates and being very easy to scatch. It is quite common for Nero Portoro random slabs to be strengthened with glass fibre netting and resin and it must be stressed that it is a very expensive limestone.
Products: Suitable for construction projects both commercial and domestic, prefabricated countertops/worktops, vanities, tiles, backsplashes, paving, fireplaces and memorials.
Surface Finish: Nero Portoro Limestone looks best with a gloss polished surface but is also available as honed, leather/satin, river-washed/antique, thermal/flamed, brushed and sandblast finish.
Sealing: Test with a small sample. It is possible that a sealant can be used on Nero Portoro limestone however excessive attempts at sealing it could actually create a residue film build-up.
Block Sizes: This is a quarry yielding selectable, grades of limestone with blocks suitable for gangsaw size down to economical tile-sized blocks. For commercial projects it is important to ensure that blocks are selected from the same quarry face. Quarry production is quite small with varying block sizes, large blocks are not common.
Rough blocks are usually exported by Break Bulk however intermodal containerisation is available at extra cost. Finished products are packed into sea-worthy wooden crates and loaded into containers.
Quarry Location: Nero Portoro limestone is quarried near Portovenere, Isola Palmaria, Provincia di La Spezia, Riviera Apennines, Liguria, Italy.
Synonyms: Black Portoro, Nero Portoro, Port d'Or, Porte-Or, Portor, Portora, Portorro
Limestone: A sedimentary rock wholly or in large part composed of calcium carbonate. The primary source of the calcite is usually marine organisms, which settle out of the water column and are deposited on the ocean floors as pelagic ooze (but see lysocline for information on calcite dissolution). Secondary calcite may also be deposited in super-saturated meteoric waters, as is evidenced by the creation of stalagmites and stalactites. It is ordinarily white but may be coloured by impurities, iron oxide making it brown, yellow, or red and carbon making it blue, black, or grey. The texture varies from coarse to fine. Most limestones are formed by the deposition and consolidation of the skeletons of marine invertebrates; a few originate in chemical precipitation from solution. Limestone deposits are frequently of great thickness.
Mineral Composition: Average by %
Compression Tensile Strength: kg/cm2
Tensile Strength After Freeze-Thaw Cycles: kg/cm2
Unitary Modulus Of Bending Tensile Strength: kg/cm2
Heat Expansion Coefficient: mm/m°C
Water Imbibition Coefficient:
Impact Strength: cm
Frictional Wear: mm
Mass By Unit Of Volume: kg/m3
Hardness (Moh's Scale):
Note: These figures and details are given for guidance purposes only, no reliance should be taken as to their accuracy.