Quartzite

Alta Quarzit

Alta Quartzite (also traded as “Polar-Quarzit” or “Midnight Sun”) is a Precambrian mica quartzite from Alta in Finnmark — one of the northernmost quarrying regions in use in Europe, above the Arctic Circle in northern Norway. The slab shows a mid to dark grey-green dimension-stone ground tone with a characteristic natural riven structure and subtle silvery mica flecks. With a quartz content of 83 %, the stone ranks among the hardest and most resistant natural materials in Europe. At ROSSITTIS we fabricate Alta Quartzite into heavy-duty external floor coverings, paving, polygonal flags, treads and risers, facade elements, wall copings and pool surrounds with a Nordic, understated dimension-stone character.

Petrographisch ein Glimmerquarzit (auch „mica quartzite" oder „muscovite quartzite") – ein hochgradig metamorphes Silikat-Gestein aus dem Paläoproterozoikum (über 2 Milliarden Jahre alt), das zur Familie der präkambrischen Schichtquarzite des fennoskandischen Schilds gehört. Mineralbestand: 83 % Quarz, ergänzt durch Muskovit (silbrig glänzender Glimmer), Plagioklas, Chlorit und Erzminerale. Die Lagerstätte befindet sich bei Alta in der Provinz Finnmark, oberhalb des nördlichen Polarkreises in Nord-Norwegen (etwa 70° nördlicher Breite) – eine der nördlichsten aktiv genutzten Naturstein-Förderungsgebiete Europas. Im DNSA als „ALTA" geführt; weitere Handelsnamen: „Polar-Quarzit" und „Midnight Sun". Die Sortierung wird laut DNSA als „sehr häufig in Deutschland verwendet" geführt – seit Jahrzehnten ist Alta Quarzit eine etablierte Wahl für anspruchsvolle Außenanwendungen.

Quartzite Norway Frostbeständig Säurebeständig 2.710 kg/m³

Available as: Slabs, Skirting, Paving slabs, Tiles and flooring slabs, Polygonal flagstones, Treads & risers · 3 of 40 reserved

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About Alta Quarzit

Background. Alta Quartzite is one of the most important Norwegian dimension stones and, under the DNSA classification, one of the European quartzites “very frequently used in Germany”. The selection is listed in the DNSA as “ALTA” and is also offered under the trade names “Polar-Quarzit” and “Midnight Sun” — a reference to its Nordic, sub-Arctic origin. For decades Alta Quartzite has been an established choice for demanding external applications in German and central European architecture — squares, pedestrian zones, prestige walkways, stairs and facade constructions. The selection is traditionally fabricated as a riven natural stone slab and is known for its exceptionally high technical load-bearing capacity.

Geology and occurrence. Petrographically, Alta Quartzite is a mica quartzite (also referred to as muscovite quartzite) — a highly metamorphic silicate rock more than two billion years old (Palaeoproterozoic) belonging to the family of Precambrian bedded quartzites of the Fennoscandian Shield. Its mineral composition is exceptionally quartz-dominated: 83 % quartz, supplemented by muscovite (a silvery, lustrous mica) and smaller proportions of plagioclase, chlorite and ore minerals. The high quartz content makes the rock extremely resistant to mechanical loading, chemical weathering and frost. The deposit lies near Alta in the province of Finnmark, in the far north of Norway, above the Arctic Circle (at roughly 70° northern latitude) — one of the northernmost natural stone quarrying areas in active use in Europe.

Appearance. The ground tone is a mid to dark grey-green dimension-stone grey with subtle warm or cool undertones depending on the incidence of light and on the batch. The natural riven face shows a characteristically lively mineral grain with silvery, lustrous muscovite flecks that give the slab a subtle pearly shimmer. From a middle distance the surface reads as a calm grey dimension-stone field with Nordic austerity; close up one discovers the fine crystalline mineral structure with its characteristic mica sparkle. The selection cannot be polished — that is inherent to the material; the natural riven texture is the defining feature, both aesthetically and technically.

Technical properties (DNSA values). Bulk density 2,710 kg/m³, compressive strength 260.8 MPa (246.6 MPa after frost — a minimal reduction from freeze-thaw cycling), flexural strength 38.4 MPa (exceptionally high — roughly twice that of typical granites), water absorption 0.10 % (very low), abrasion group 6.4 cm³/50 cm², Mohs hardness approximately 7. Alta Quartzite therefore sits at the very top of the hard rock family and is statically and mechanically suited to the highest loads. Frost- and de-icing-salt-resistant (confirmed by the DNSA — only a minimal reduction in strength after frost cycles), fully UV-stable and, as a pure quartz-dominated silicate rock, fully acid-proof. Heat-resistant.

The ROSSITTIS range. The finishes currently available from stock are listed in the »Finishes« block further down this page. From the slabs we fabricate paving and floor coverings in bespoke or standard formats, polygonal flags in an irregular natural cut, treads and risers for external stairs, window sills, skirtings, wall copings, pool surrounds, facade elements and dimension-stone components.

Comparison. Within the family of Nordic bedded quartzites, Alta Quartzite positions itself as the premium choice established on the German market, with the highest technical profile. Related Nordic bedded quartzites are Otta phyllite (Norway, with dramatic actinolite stars), Oppdal quartzite (Norway, similar but less rich in mica), Vals quartzite (Switzerland, with more dramatic bedding lines) and Aurora slate (Scandinavia). Compared with classic paving granites such as Bohus or Vanga (Swedish), Alta Quartzite is somewhat more characterful thanks to its natural riven look — granite setts are more homogeneous, with a granular grain. Compared with southern European quartzites such as Verde Bahia (Brazil), Alta is markedly more austere and more Nordic, with a higher mica content. Swiss Vals quartzite and Norwegian Otta phyllite are stylistically related as well.

A frank assessment. Alta Quartzite is the optimum choice for any demanding external application with the highest requirements for technical load-bearing capacity, frost resistance and long-term weathering stability. The selection performs particularly strongly as high-grade external paving for squares and pedestrian zones, as stairs and treads in heavily frequented public areas, as facade cladding in Nordic architectural concepts and as wall coping for high-end garden schemes. Anyone looking for a warm, homely internal stone should turn to warm natural stone selections such as Pietra di Cardoso or to sandstone-like types; anyone who needs a smooth, polishable surface should switch to classic quartzites such as Cristallo Quartzite; anyone who wants the natural riven look in a warmer tone should choose Otta phyllite.

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 2.710 kg/m³

Druckfestigkeit 260,8 MPa

Biegezugfestigkeit 38,4 MPa

Wasseraufnahme 0,10 %

Frostbeständig Ja

Säurebeständig Ja

Finishes

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

Spaltrau kalibriert

Wie spaltrau (natürlich gespaltene, raue Mattoberfläche), zusätzlich mit kalibrierter Rückseite: Die Plattenunterseite ist plan geschliffen für gleichmäßige Stärke und vereinfachte Verlegung. Empfohlen für Außenbereiche, Pflasterflächen und Fassadenverklebungen mit Anspruch an präzise Maßhaltigkeit.

Spaltrau

Die Oberfläche entspricht einer natürlichen Spaltung des Gesteins — matte, raue Anmutung mit hoher Rutschsicherheit und naturhafter Wirkung. Empfohlen für Außenbereiche, Mauerverkleidungen und stark beanspruchte Pflasterflächen. Die Plattenstärke kann durch die spaltraue Bearbeitung leicht variieren.

Care & fabrication

Cleaning. Outdoors, clear water and a soft brush or broom are sufficient. Heavier soiling can be removed with pH-neutral natural stone cleaners and a pressure washer (at reduced pressure and with a fan jet, never a concentrated jet held on one spot). Indoors, warm water and a soft cloth or mop are sufficient.

Do not use. Aggressive specialist chemicals are not required on this quartzite. Avoid heavy pressure washers with a pencil jet, as they can alter the natural riven faces.

Sealing. Not required outdoors — with water absorption of 0.10 %, Alta Quartzite is virtually non-porous. Indoors, on horizontal surfaces (floors, stairs), a sealer can make cleaning and care easier, because the natural riven texture can pick up somewhat more dirt than a smooth polish.

Outdoors and frost. Outstandingly suited (DNSA-confirmed frost-resistant, with only a minimal reduction in strength after freeze-thaw cycles). For decades Alta Quartzite has been the classic choice for heavily loaded external floor coverings in central European climates. De-icing salt and winter grit are no problem — the quartz mineralogy is fully acid- and alkali-proof. In spring we recommend cleaning with clear water to remove road salt residues and winter deposits.

Kitchen and bathroom. Recommended only with reservations. The natural riven surface has a striking feel, but is rather unconventional for kitchen worktops or internal surfaces that need to be wiped smooth. For wall cladding or special accents in bathroom and kitchen, however, the selection is highly impressive with its Nordic dimension-stone character. The finishes currently available from stock are listed in the »Finishes« block further down this page.

Floors and stairs. The classic application. With its high compressive strength (260.8 MPa) and an abrasion group of 6.4 cm³/50 cm², Alta Quartzite is one of the most robust natural stone options in the world for heavily used public floor areas, squares, pedestrian zones and commercial entrance areas. The natural riven surface provides inherent slip resistance (R10 to R12 depending on batch and finishing method).

Facades. One of the classic domains of this selection. Alta Quartzite can be installed as a ventilated facade panel with factory-fitted edge anchoring or as a mortar-bedded external wall cladding. The natural riven surface brings a distinctive natural stone appearance to contemporary architectural concepts.

Scratches and repair. At Mohs 7, Alta Quartzite is one of the most scratch-resistant natural materials there is. The natural riven surface is inherently irregular — minor mechanical damage often blends unobtrusively into the natural appearance. Deeper damage can be remedied by replacing the affected piece.

Frequently asked questions

What kind of material is Alta Quartzite?

Petrographically a mica quartzite — a highly metamorphic silicate rock from the Palaeoproterozoic (more than 2 billion years old) belonging to the family of Precambrian bedded quartzites of the Fennoscandian Shield. It has an 83 % quartz content, supplemented by muscovite (a silvery, lustrous mica), plagioclase and chlorite. The deposit lies near Alta in the province of Finnmark, above the Arctic Circle in northern Norway.

What do the names “Polar-Quarzit” and “Midnight Sun” mean?

“Polar-Quarzit” is the German-language trade designation, referring to the sub-Arctic origin above the northern Arctic Circle (Alta lies at roughly 70° northern latitude). “Midnight Sun” is the English trade designation, referring to the natural phenomenon of the midnight sun — characteristic of the northernmost Norwegian quarrying regions. In the DNSA the selection is listed simply as “ALTA”.

What technical values does Alta Quartzite have?

DNSA values: bulk density 2,710 kg/m³, compressive strength 260.8 MPa (exceptionally high), flexural strength 38.4 MPa (roughly twice that of typical granites), water absorption 0.10 % (virtually nil), abrasion group 6.4 cm³/50 cm², Mohs hardness approximately 7. Frost- and de-icing-salt-resistant (DNSA-confirmed, with only a minimal reduction in strength after frost cycles), UV-stable, fully acid-proof.

What exactly does Alta Quartzite look like?

A mid to dark grey-green dimension-stone ground tone with subtle warm or cool undertones and a characteristic natural riven structure. The natural riven face shows a lively mineral grain with silvery, lustrous muscovite flecks that give the slab a subtle pearly shimmer.

Is Alta Quartzite suitable for external applications?

Yes, outstandingly so — this is the classic domain of this selection. With its exceptionally high compressive strength (260.8 MPa), flexural strength of 38.4 MPa, low water absorption (0.10 %) and DNSA-confirmed frost resistance, Alta Quartzite is among the most robust natural stone options in Europe. A classic choice for heavily loaded external paving, squares, pedestrian zones, stairs and facade cladding.

Can Alta Quartzite be polished?

Only to a limited extent, for reasons inherent to the material. The selection is classically fabricated as a riven natural stone slab — the natural riven surface is the defining feature, both aesthetically and technically. Polished Alta slabs are theoretically possible but unusual — anyone looking for a polishable quartzite selection should switch to Cristallo Quartzite, Mont Blanc or other polishable quartzites.

Which cleaners may I use?

Warm water, all pH-neutral stone and general-purpose cleaners and mild washing-up foam are permitted. With its pure quartz mineralogy, quartzite is resistant to almost all chemicals. Avoid heavy pressure washers with a pencil jet, as they can alter the natural riven faces.

Alta Quartzite or classic granite setts?

Both are high-grade hard rock options for external paving with a centuries-long track record. Alta Quartzite (a Norwegian mica quartzite, 83 % quartz, with a characteristic natural riven surface) is more characterful and more Nordic, with a subtle mica shimmer; classic granite setts (for example Swedish Bohus or Galician Blanco Estrella, with a granular salt-and-pepper grain) are more homogeneous and available in more tonal values. The choice is a question of style: Nordic dimension-stone authenticity (Alta) against a classic granite grain.