Gabbro

Listed in our range under Granite.

Nero Assoluto Zimbabwe J

Nero Assoluto Zimbabwe J is the standard quality class of the world-famous deep black norite/gabbro from the Mutoko quarrying area north-east of Harare in Zimbabwe. An exceptionally dense (3,040 kg/m³), fine-grained black ground mass with subtly visible fine plagioclase mineral dots — DNSA-confirmed frost- and acid-resistant (DNSA 4628). Sister grade to the premium class C1 (same quarry, same stone, somewhat less strictly selected). Also traded internationally as Rhodesia Black, Zimbabwe Black, Negro Austral and Mutoko Black; used for kitchen worktops, bar counters, exterior façades, floor areas, stairs, headstones and demanding building applications.

Nero Assoluto Zimbabwe J is petrographically a fine-grained norite/gabbro (DNSA 4628), that is, a plutonic igneous rock with a high plagioclase and pyroxene content — not a basalt in the strict sense (basalt would be the effusive variant; the Mutoko stone is an intrusive plutonic variant). In the international trade it is traditionally listed as “black granite”, because in fabrication it is handled like a classic hard stone. At ROSSITTIS we classify Nero Assoluto Zimbabwe J within the granite family in line with trade practice, following trade convention.

Gabbro Zimbabwe Frostbeständig Säurebeständig 3.040 kg/m³

Available as: Slabs

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About Nero Assoluto Zimbabwe J

Nero Assoluto Zimbabwe J shows a deep, almost pure black ground tone with a fine-grained, isotropic mineral structure. The slab surface looks closed and calm — on close inspection, fine plagioclase feldspar dots are visible as delicate paler mineral accents, which give the J grade a somewhat subtler, lively mineral character than the still more even premium grade C1. The J class is the standard quality designation of the Mutoko quarries — a proven, fully everyday-fit deep black granite with no pronounced vein pattern or layering, but with the characteristic fine mineral structure inherent in natural stone. On a polished surface the stone develops the famous “Assoluto” effect: an almost mirror-like deep black with impressive optical depth. The mineral structure is isotropic (non-directional), which means there are no vein courses, no layering and no preferred orientations. Compared with the premium class C1, characterised by a particularly even selection with no visible mineral flecking, the J class offers the same technical performance with somewhat more visible natural mineral variety — which many customers value precisely as an authentic characteristic of natural stone.

Geologically, Nero Assoluto Zimbabwe J is a Precambrian norite/gabbro — an igneous plutonic rock that formed during early Earth history (over 2.5 billion years old) in the Great Dyke of Zimbabwe. Its main constituent is plagioclase feldspar (labradorite-bytownite) together with dark pyroxene minerals (augite/hypersthene) and accessory magnetite minerals — the latter two are responsible for the intense black colouring and the high bulk density of 3,040 kg/m³ (markedly above typical granite at ~2,700 kg/m³). The quarrying area lies in Mutoko, a region around 140 km north-east of Harare, the capital of Zimbabwe. The DNSA dimension stone records list the material under the identifier 4628 with complete technical data; a second entry, DNSA 3360, refers to the older trade name “Rhodesia Black” from the colonial period. Several synonyms circulate in international trade: Rhodesia Black, Zimbabwe Black, Negro Austral (Spanish trade name), Mutoko Black and occasionally Black Impala (for the mineralogically related South African version). The designation “Nero Assoluto Zimbabwe” comes from the Italian marble industry and has established itself as a premium trade name.

Technically, Nero Assoluto Zimbabwe J shows exceptional values that make it one of the mechanically most capable commercially traded natural stones: bulk density 3,040 kg/m³ (around 12 % heavier than typical granite), compressive strength 228 MPa (very high), flexural strength 31 MPa (exceptional), water absorption only 0.11 % (extremely low), Mohs hardness 6.5–7. According to the DNSA the stone is expressly frost- and acid-resistant — both properties are officially confirmed in the data sheet. Polished surfaces are durable outdoors as well. This makes Nero Assoluto Zimbabwe J fully fit for the most demanding interior and exterior applications, including extreme structural loading, exterior façades in locations with heavy exposure to the weather and intensively used public floor areas. The technical values of the J class are identical to those of the premium C1 class — the difference lies purely in the visual selection.

At ROSSITTIS we carry Nero Assoluto Zimbabwe J as a raw slab in 20 mm and 30 mm thickness, in tiles for floor and wall applications, as tread and riser for stairs, window sill, skirting, bar counter and for project-specific cutting. The stone is also ideally suited as pool coping, as a fountain element and for exterior façades. The surface finishes available from stock are listed in the »Finishes« block further down.

Compared with the sister grade C1 (the premium class with a particularly even mineral distribution and no visible plagioclase accents — the highest optical consistency), the J class offers the same technical performance with somewhat more authentic natural mineral variety at usually more favourable prices. For projects with the highest aesthetic demands in large-area wall claddings or bookmatched settings we recommend C1; for most standard applications — kitchen worktops, floor areas, stairs, exterior façades, bar counters, headstones and general building applications — the J class is the practical and economically more attractive choice. Compared with other deep black building stones such as Belfast Black (Irish volcanic rock, often with a greenish cast), Star Galaxy (an Indian granite with golden bronze mica dots), Nero Africa Premium (South African, somewhat less even) or Nero Imperial (Indian, coarser-grained), Nero Assoluto Zimbabwe J belongs to the top class of black building stones with particularly low water absorption and high block-to-block consistency. For architectural projects with durable, value-retaining black surfaces — designer kitchens, hotel entrances, prestige buildings, exterior façades with the highest stability against weathering, headstones and memorials — Nero Assoluto Zimbabwe J is a planning-reliable and economically attractive choice.

In stock

Current availability from our warehouse.

5 slabs in stock · plus 1 block

Thicknesses: 3 cm · Finishes: geflammt + water cleaned · Available as: Slabs

Updated daily from our live stock.

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Technical data

Guide values for the stone type, taken from manufacturer and test reports. Natural stone is a natural product — individual batches and slabs can differ. For critical applications, request slab-specific test data.

Rohdichte 3.040 kg/m³

Druckfestigkeit 228,0 MPa

Biegezugfestigkeit 31,0 MPa

Wasseraufnahme 0,11 %

Frostbeständig Ja

Säurebeständig Ja

Suitability by application

Care & fabrication

As a norite/gabbro, Nero Assoluto Zimbabwe J is an exceptionally robust hard stone with extremely low water absorption (0.11 %), confirmed frost and acid resistance (DNSA) and very high compressive and flexural strength. Wine, lemon juice, vinegar, cola, sanitary cleaners or limescale removers leave no etch marks as they would on marble or limestone — the stone is markedly easier to care for and ideally suited to intensive everyday use.

For polished black surfaces one particularity applies: the mirror-like depth shows every detail of water marks and wipe streaks all too clearly, because the pure black offers no masking effects. Dry cleaning with a polished microfibre cloth after damp wiping is obligatory for a clear appearance — on pale or patterned stones, streaks are less disturbing than on Nero Assoluto. The surface finishes available from stock are listed in the »Finishes« block further down.

For interior applications we recommend a light impregnation on a silane or polysiloxane basis at first installation. On polished surfaces a refresh every 8–10 years is enough depending on use; on heavily used kitchen worktops, check every 5 years. Impregnation protects against grease rings on highly polished surfaces, which can otherwise be briefly visible (though they often also disperse of their own accord after a short time without impregnation, because the stone is extremely dense).

Daily care is done with a pH-neutral natural stone cleaner and a soft cloth or microfibre mop. Clear warm water is usually enough. Acidic cleaners are fundamentally unproblematic (the stone is acid-resistant), but should nevertheless not be used, because they can attack the impregnation.

For kitchen worktops, Nero Assoluto Zimbabwe J is outstandingly suited: exceptionally resistant to cuts and scratches, insensitive to heat, acid-resistant and with excellent stain repellency thanks to the extremely low water absorption. Hot pots and pans can be set down directly for short periods, though longer heat exposure above 250 °C should nevertheless be avoided. The dark ground tone shows crumbs, flour and food residues more clearly than pale grades — that is an aesthetic question, not a disadvantage of the material.

For exterior applications, Nero Assoluto Zimbabwe J is stable against weathering over the long term, with its DNSA-confirmed frost resistance, exceptional strength and low water absorption. The surface finishes available from stock are listed in the »Finishes« block further down. For pool surrounds, exterior terraces and fountain surrounds a slip-resistant textured finish is obligatory — on smooth exterior surfaces there is a high risk of slipping when wet.

In hot climate zones the dark ground tone stores a great deal of solar energy — for exterior surfaces used barefoot, such as pool surrounds, this can lead to unpleasant surface temperatures in Mediterranean or subtropical climates. A flamed finish slightly reduces solar heating through a higher albedo; alternatively use it in shaded areas or combine it with cooled irrigation.

Frequently asked questions

What does the J designation mean?

J is the standard quality class of Nero Assoluto Zimbabwe — a proven, fully everyday-fit grade with the same technical values as the premium class C1, but somewhat less strictly selected. While C1 is chosen for particularly even, inclusion-free block-to-block consistency in large-area projects, J offers the same performance at usually more favourable prices with somewhat more authentic natural mineral variety — the fine plagioclase mineral dots are more subtly visible.

What is Nero Assoluto Zimbabwe J geologically?

Nero Assoluto Zimbabwe J is petrographically a fine-grained norite/gabbro — an igneous plutonic rock from the Great Dyke of Zimbabwe (over 2.5 billion years old). Its main constituents are plagioclase feldspar (labradorite-bytownite), pyroxene minerals and magnetite. The DNSA lists the material under identifier 4628. In international trade the stone is traditionally traded as “black granite”; at ROSSITTIS we classify it in the customary way in the granite family.

Which synonyms are there?

In international trade, Nero Assoluto Zimbabwe J also runs under the designations Rhodesia Black (an older trade name from the colonial period, DNSA 3360), Zimbabwe Black, Negro Austral (Spanish trade name), Mutoko Black and occasionally Black Impala. The designation “Nero Assoluto” comes from the Italian marble industry and has established itself internationally as a premium trade name. All designations refer to the same stone from the Mutoko quarrying area.

What technical values does Nero Assoluto Zimbabwe J have?

Exceptionally strong values (identical to the premium C1 class): bulk density 3,040 kg/m³ (around 12 % heavier than typical granite), compressive strength 228 MPa, flexural strength 31 MPa, water absorption 0.11 % (extremely low), Mohs hardness 6.5–7. Frost and acid resistance confirmed by the DNSA. This makes Nero Assoluto Zimbabwe J fully fit for the most demanding interior and exterior applications.

J or C1 — which grade suits my project?

Both grades are technically identical (same quarry, same stone). The difference lies purely in the visual selection: C1 is the premium grade with a particularly even mineral distribution and no visible plagioclase accents — the highest optical consistency for demanding bookmatched settings or large-area wall claddings with long slab sequences. J is the standard grade with somewhat more authentic natural mineral variety — ideal for kitchen worktops, floor areas, stairs, exterior façades and general building applications, where the subtle mineral variety is even felt as an advantage.

Which finishes are there for Nero Assoluto Zimbabwe J?

The surface finishes available from stock are listed in the »Finishes« block on this page.

What is “flamed + watercleaned”?

A combined special treatment: the slab surface is first textured with high-temperature flame treatment (minerals split off thermally, the surface becomes rough and slip-resistant), then cleaned with a high-pressure water jet (watercleaned) in order to smooth the sharp fracture edges and produce a more pleasant, less aggressive feel. The surface retains the slip-resistant textured effect, but is markedly more pleasant for barefoot use and for care than a purely flamed finish.

Is Nero Assoluto Zimbabwe J suitable for a kitchen worktop?

Outstandingly suited — it is regarded as one of the best stones for kitchen worktops there is. With a Mohs hardness of 6.5–7, extremely low water absorption (0.11 %), exceptionally high compressive strength (228 MPa) and full acid resistance, the stone is resistant to cuts, scratches and heat and absorbs no acids from wine, lemon or vinegar. The J grade with its subtle plagioclase mineral dots is often even preferred, because the fine mineral variety makes the deep black picture look livelier and more authentic.

What does Nero Assoluto Zimbabwe J cost?

The price depends on the batch, thickness, surface finish and fabrication — with natural stone there is no serious flat rate per square metre. Business customers see prices once their B2B account is activated; private customers receive a complete quote through a fabricator near them.