Quartzite

Bronzzo

Bronzzo is an exceptional Brazilian quartz-grunerite gneiss from southern Bahia with a unique metallic bronze material effect in deep mahogany brown, luminous gold and black accents — the feel recalls hammered bronze or patinated copper sheet. Also traded internationally as Bronzo, Bronzo Granite and Bronzo Marron; used for expressive kitchen worktops, bar counters, wall cladding, statement interior surfaces and prestige external applications with high material ambition.

Bronzzo ist petrographisch ein Quarz-Grunerit-Gneis (etwa 72 % Grunerit, 22 % Quarz, 6 % opake Mineralien) mit ungewöhnlich hoher Rohdichte (3.286 kg/m³). Im Handel teils als Granit (Bronzo Granite) geführt; bei ROSSITTIS klassifizieren wir das Material in der Quarzit-Familie wegen Mohshärte 7 und voller Säurebeständigkeit.

Quartzite Brazil 3.286 kg/m³

Available as: Slabs

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About Bronzzo

Bronzzo lives on a unique metallic bronze material effect that has few equals in the worldwide natural stone family. The ground tone is a deep, rich mahogany to copper brown with warmly luminous golden and ochre-brown accents and black anthracite areas. Across the whole slab surface are distributed characteristic flowing vein bands and irregular patterns recalling hammered bronze, patinated copper sheet or weathered wood — not a strictly geometric striping, but an organic, almost painterly distribution of the mineral fibres. Isolated light grey and creamy quartz veins set subtle accents of light in the otherwise warm bronze composition. On the satin-honed surface the stone develops a soft, matt shimmer with a clear depth — the golden mineral areas catch light and intensify the bronze feel in a quiet manner that is tolerant in everyday use. Every slab pattern is a unique one-off — with this material it is particularly worth making the selection from real slab images, because the distribution of the bronze, gold and black areas varies considerably from block to block.

Geologically, Bronzzo is an exceptional mineral rock from southern Brazil — petrographically a quartz-grunerite gneiss or quartzite with an unusual mineral composition: around 72 % grunerite (an iron-magnesium amphibole from the anthophyllite-cummingtonite series), 22 % quartz and 6 % opaque minerals. This unusually high concentration of grunerite is responsible for two particular properties: first, for the unique bronze-golden colouring with its metallic feel, because the fibrously crystallised grunerite crystals reflect light directionally; second, for the unusually high bulk density of 3,286 kg/m³, which lies markedly above typical granite (2,700 kg/m³) and quartzite (2,650 kg/m³) values. The stone is quarried in the quarries of southern Bahia. In international trade, Bronzzo runs under several synonyms: Bronzo, Bronzo Granite, Bronzzo Granite and Bronzo Marron Granite — the commercial 'Granite' addition is not entirely correct geologically, but is widespread in the trade. At ROSSITTIS we classify Bronzzo, as is customary in the trade, as a quartzite, because the material is handled in fabrication like a true quartzite (Mohs hardness 7) and shows full acid resistance.

Technically, Bronzzo shows exceptional values. Bulk density is unusually high at 3,286 kg/m³ (about 20 % heavier than typical granite), compressive strength an impressive 270.3 MPa, flexural strength an exceptional 38.9 MPa (about twice as high as classic granite) and water absorption a low 0.15 %. Mohs hardness is 7. These values make Bronzzo one of the mechanically highest-performing natural stones traded commercially — cut-, scratch- and heat-resistant, frost-resistant and fully acid-resistant. Wine, lemon juice, vinegar or acidic bathroom cleaners leave no etch marks. The high density has to be allowed for structurally in large-area installations — on external façades or large wall cladding, higher loads arise than with standard granite.

At ROSSITTIS we carry Bronzzo as an unsized slab for luxurious kitchen and bathroom worktops, bar counters, wall cladding, fireplace surrounds and prestige statement surfaces, in tiles for floor and wall applications, as tread and riser for stairs, and as window sill, skirting, fountain element and for project-specific cutting. The stone is also ideally suited to pool coping and external façades. The surface finishes currently held in stock are listed in the »Finishes« block further down.

Compared with classic brown granite classics such as Tan Brown (an Indian granite, evenly fine-grained) or Imperial Brown (with more pronounced coloured points), Bronzzo brings a completely different, unique bronze-metallic feel with a visual effect that has few equals. Compared with expressive Brazilian quartzites such as Verde Picasso (with a horizontally layered olive-green band structure) or Vittra Crystal (with a storm-grey, arctic-white and oxide-red composition), Bronzzo brings the characteristic warm copper-mahogany character, particularly fitting for architecture with a warm industrial or luxury ambition. For architectural projects with a dramatic warm character — designer kitchens with bronze or copper accents, hotel lobbies with a warm atmosphere, bar counters in high-end restaurants, spa areas and prestige wall and façade surfaces — Bronzzo is a very exclusive and expressive choice in the upper premium segment of the Brazilian exotic hard stones.

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 3.286 kg/m³

Druckfestigkeit 270,3 MPa

Biegezugfestigkeit 38,9 MPa

Wasseraufnahme 0,15 %

Finishes

Bronzzo is available in a range of finishes. The finish affects appearance, feel and the care it needs.

Satiniert

Die Oberfläche wird gebürstet — weichere Minerale werden gezielt entfernt, es entsteht eine leichte Tiefe und mattes Erscheinungsbild. Geaderte Quarzite erhalten so eine besondere Charakteristik. Säurebeständig und kratzfest, pflegeleicht im Alltag — beliebte Alternative zur Politur in modernen Küchen und Wohnräumen.

Care & fabrication

As a Brazilian quartz-grunerite gneiss, Bronzzo is an exceptionally robust hard rock with low water absorption (0.15 %), full acid resistance and a Mohs hardness of 7. Wine, lemon juice, vinegar, cola, bathroom cleaners or descalers leave no etch marks as they would on marble or limestone — the stone is markedly easier to look after and ideally suited to intensive everyday use.

For interior applications we recommend a silane- or polysiloxane-based sealer at first installation. With normal use, 5-10 years can pass between sealer refreshes; on heavily used kitchen worktops or external applications, check every 2-3 years. Sealing protects against deep penetration by oil, grease and pigments — on the heterogeneous surface of Bronzzo, discolouration can otherwise show up on the lighter quartz areas.

Daily care is carried out with a pH-neutral natural stone cleaner and a soft cloth or microfibre mop. Clear warm water is usually sufficient. Acidic cleaners are in principle unproblematic, but should nevertheless not be used, because they can attack the sealer. The surface finishes currently held in stock are listed in the »Finishes« block further down.

Bronzzo is outstandingly suited to kitchen worktops: cut- and scratch-resistant, not sensitive to heat (hot pots and pans can be set down directly for short periods, though longer heat exposure above 200 °C should still be avoided), acid-resistant and with excellent stain repellency thanks to the low water absorption. The high compressive strength (270.3 MPa) and exceptional flexural strength (38.9 MPa) support heavier structural loads. The expressive bronze-golden surface disguises small marks of use astonishingly well. For external applications, Bronzzo with its low water absorption is frost-resistant and stable against long-term weathering. Important for planning: the unusually high bulk density of 3,286 kg/m³ (about 20 % heavier than standard granite) has to be allowed for structurally in large-area installations — external façades, large wall cladding or widely overhanging bar counters require correspondingly designed substructures. The surface finishes currently held in stock are listed in the »Finishes« block further down.

For pool surrounds, external terraces and fountain surrounds, a slip-resistant textured finish is mandatory — on smooth external surfaces there is a high risk of slipping when wet. In areas with frequent salt contact (de-icing salt, pool chlorine) we recommend an additional annual refresh of the sealer. The dark bronze-brown ground tone stores a great deal of solar energy in hot climate zones — for pool areas in the south, combine where appropriate with locally cooled irrigation.

Frequently asked questions

What makes Bronzzo so special?

Bronzzo is one of the most unusual natural stones in the range. Its mineral composition of about 72 % grunerite (an iron-magnesium amphibole), 22 % quartz and 6 % opaque minerals is rare in the worldwide natural stone range — it gives the stone its unique metallic bronze colouring with a hammered-metal character. The unusually high bulk density of 3,286 kg/m³ (around 20 % heavier than typical granite) and the exceptional flexural strength of 38.9 MPa (about twice as high as classic granite) also make it one of the mechanically highest-performing natural stones.

What is Bronzzo geologically?

Bronzzo is a Precambrian quartz-grunerite gneiss or quartzite from southern Bahia in Brazil. In international trade the stone is frequently described incorrectly as a 'granite' (Bronzo Granite) — geologically, however, it is a metamorphic hard stone, not an igneous granite. At ROSSITTIS we classify Bronzzo, as is customary in the trade, within the quartzite family, because it is handled in fabrication like a true quartzite and shows full acid resistance.

Is Bronzzo suitable for a kitchen worktop?

Outstandingly suited. With a Mohs hardness of 7, very low water absorption (0.15 %), exceptionally high compressive strength (270.3 MPa) and full acid resistance, Bronzzo is cut-, scratch- and heat-resistant and does not absorb the acids in wine, lemon or vinegar. The expressive bronze-golden surface disguises small marks of use astonishingly well. For a kitchen worktop with a dramatic warm material effect and full everyday suitability, the stone is a very fitting choice.

Which finishes are available for Bronzzo?

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

Where does Bronzzo come from?

Bronzzo comes from the quarries in the southern state of Bahia in Brazil — a region known for the production of exotic quartzites and unusual hard stones. Internationally the material also runs under the synonyms Bronzo, Bronzo Granite, Bronzzo Granite and Bronzo Marron Granite. The quarry designation 'SuperClássico' denotes the premium grade with a particularly intense bronze-golden colouring.

How do I clean and care for Bronzzo?

As a quartz-grunerite hard stone, Bronzzo is very easy to look after: daily care with a pH-neutral natural stone cleaner and a microfibre cloth is sufficient. We recommend sealing at first installation; for interior applications a refresh interval of 5-10 years depending on use, and on heavily used kitchen worktops or outdoors, check every 2-3 years. Acidic cleaners are in principle unproblematic, but should nevertheless not be used. Dry cleaning with a soft microfibre cloth after damp wiping is advisable for the full metallic bronze depth.

What do I need to consider structurally for large-area Bronzzo installations?

The unusually high bulk density of 3,286 kg/m³ (about 20 % heavier than standard granite at ~2,700 kg/m³) has to be allowed for structurally in large-area installations. A 3 cm thick Bronzzo slab weighs about 99 kg/m² — correspondingly more than the 81 kg/m² of a comparable granite slab. On external façades, large-area wall cladding or widely overhanging bar counters, substructures and fixings have to be designed correspondingly stronger. For smaller applications (standard kitchen worktops, window sills, stair treads) the higher density is unproblematic.