Belfast Black Granite
Return to granite samples page.
Synonyms: Absolute Black, Afrika Schwarz, Belfast, Negro Belfast, Nero Assoluto, Nero Assoluto Belfast, Nero Assoluto Dunkel, SSY, SSY Granit
Location: Belfast Black granite is quarried near Wapadskloof, Belfast, Mpumalanga, South Africa, and this is most probably the first granite referred to as Nero Assoluto by the Italian stone industry.
Description: Belfast Black granite is a fine-grained, black gabbro/norite of the Precambrian period. This stone internationally may be nominated as a granite but in the area of application of the European Standard this stone must be nominated as a gabbro.
A small sample of Belfast Black granite is usually representative not having a wide variation in colour and veining however swatch samples must be approved for large projects to ensure that the blocks are all extracted from the same quarry face for matching purposes. Ideal for both interior and exterior use, Belfast Black granite is frost free and polish constant.
Technical and Physical Characteristics:
Bulk density: 2.94 - 3.00 kg/dm≥
Bending strength: 24.52 - 33.6 N/mm≤
Compression breaking load: 264.5 - 312.8 N/mm≤
Water absorption: 0.15 weight-%
Gabbro: A dark-coloured, coarse-grained intrusive igneous rock. Gabbro is very similar to basalt in its mineral make up. It is composed mostly of the mineral plagioclase feldspar with smaller amounts of pyroxene and olivine.
Norite: A mafic intrusive igneous rock composed largely of the calcium-rich plagioclase labradorite and hypersthene with olivine. Norite is essentially indistinguishable from gabbro without thin section study under the petrographic microscope. The principal difference between norite and gabbro, however, is the type of pyroxene of which it is composed; norite is predominately composed of orthopyroxenes, largely high magnesian enstatites, whereas the principal pyroxenes in gabbro are clinopyroxenes, generally medially iron-rich augites.