Angola Black Granite From Angola
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Description: Angola Black Granite is a coarse-grained, dark blue/black anorthosite 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 an anorthosite. A small sample of Angola 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. 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. Angola Black Granite is suitable for both interior and exterior use futhermore is frost resistant and with a constant polish.
Black Granite Shades
As a generalisation most black granite quarries have varying shades of black. This variation in shading is completely natural and usually occurs with the ground level of the quarry being lighter with the deeper the granite is quarried becoming darker, however some quarries may vary in shade along its length or width. The experienced quarryman knows where the lighter and darker shades are and can supply to the customer's preferences. All of our Indian black granites are from the Deccan Plateau.
NOTE: It is a fact that some unscrupulous dealers will actually dye the lighter shades and try to sell them as the Ultimate Black, Premium Black or Absolute Black product at its correspondingly higher price, with totally normal usage these "doctored" blacks will lose their artificially applied darkness. To check for dying try the lemon juice or acetone test. Do ensure that the granite is washed clean before doing this otherwise it may simply be general dirt. Take a clean white rag and apply some lemon juice or acetone to the granite surface. If any residue or black appears on the rag then it has been dyed. Also, if you have several small sample choices, leave a drop of the lemon juice for five minutes on the polished surface, wipe the surface clean and observe the results, once again any dull spot or patch and the material has been doctored.
Needless to say we never use colour enhancers.
To assist all potential black granite purchasers we have produce an Absolute Black Granite Guide.
Products: Suitable for construction projects both commercial and domestic, prefabricated countertops/worktops, vanities, tiles, backsplashes, paving, fireplaces and memorials.
Premium Quality Slab Sizes 2 & 3cm
Standard Slab Sizes 2 & 3cm
Granite Countertops 2 & 3cm
Calibrated Tiles: Standard sizes available are:
305 x 305 x 10 mm (12" x 12" x 3/8")
More granite tile and production information.
Surface Finish: Angola Black Granite 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 Angola Black granite however excessive attempts at sealing it could actually create a residue film build-up.
Block Sizes: This is a quarry yielding selectable, grades of granite 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.
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: Angola Black granite is quarried near Sa da Bandeira, Lubango, Angola.
Synonyms: Angola, Black Angola, Lapis Black, Labrador Black, Negro Angola, Negro de Angola, Nero Angola, Preto Angola
Anorthosite: A phaneritic, intrusive igneous rock characterized by a predominance of plagioclase feldspar (90-100%), and a minimal mafic component (0-10%). Pyroxene, ilmenite, magnetite, and olivine are the mafic minerals most commonly present.
Mineral Composition: Average by %
Compression Tensile Strength: 2080 kg/cm2
Tensile Strength After Freeze-Thaw Cycles: 1990 kg/cm2
Unitary Modulus Of Bending Tensile Strength: 132 kg/cm2
Heat Expansion Coefficient: 0.0065 mm/m°C
Water Imbibition Coefficient: 0.004000
Heat Expansion Rate: 0,0062 mm/m°C
Mass By Unit Of Volume: 2620 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.