Sandstone

Rainbow

Rainbow Sandstone is an exceptionally colourful Palaeozoic sedimentary sandstone from Nagaur and Jaipur in the Indian state of Rajasthan, with characteristic horizontal banded bedding in cream-white, honey-yellow, mauve-violet and subtle greenish-pink tones. Also traded internationally as Jaipur Rainbow Sandstone and Rainbow Sandstone India; used for expressive wall and façade cladding, stairs, pool surrounds, external tiles, garden paths and architectural accents with a characteristic sedimentation appearance.

Sandstone India Säurebeständig 2.090 kg/m³

Available as: Slabs, Tiles and flooring slabs

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About Rainbow

Rainbow Sandstone shows one of the most extraordinary slab patterns in the worldwide sandstone range. Across the entire slab surface run characteristic horizontal, slightly undulating sedimentation bands, formed by different iron oxide and manganese mineralisations during the original deposition in a Palaeozoic shallow sea. The colour palette is exceptionally varied: cream-white, light beige and sand-coloured layers alternate with honey-yellow, ochre, slightly red-brown, mauve-violet and subtle grey-green bands. The individual layers are not strictly linear but slightly undulating and irregular — as if the original sand layers of a branching river system or a wave-agitated shallow sea had set in stone. The flowing, organic band structure creates the rainbow slab pattern that gives the stone its name — hence the trade name Rainbow. On a honed surface the stone develops a matt, warm feel with a subtle shimmer; the individual colour bands stand out clearly legible. Every slab pattern is a unique one-off — with Rainbow Sandstone it is particularly worth making the selection from real slab images, because the distribution of the colour layers varies considerably from block to block and every slab yields a different 'geological watercolour'.

Geologically, Rainbow Sandstone is a Palaeozoic (roughly 540–250 million years old) fine-grained quartz sandstone from the district of Nagaur and the region around Jaipur in Rajasthan, northern India. The quarries lie in a region known for centuries for the production of multicoloured sandstones — the historic Maharaja palaces of Rajasthan were already built with local coloured sandstones. Petrographically the stone consists predominantly of fine-grained quartz with interstitial iron oxide mineralisations (haematite for the red/violet bands, limonite for the yellow/honey bands, manganese oxides for the greenish/darker bands). On the market the material is carried under the main name RAINBOW, with Jaipur Rainbow Sandstone as a common synonym. In international trade the designations Rainbow Teakwood (a confusion with the short designation), India Rainbow, Rajasthan Rainbow and Multicolor Sandstone also circulate. Important: several independent stones share the trade name 'Rainbow' (including an Australian and a Chinese sandstone) — when ordering, we recommend always specifying the exact supplier and the origin (India/Rajasthan).

Technically, Rainbow Sandstone shows the typical values of a moderately porous sedimentary sandstone: bulk density 2,070–2,110 kg/m³ (markedly lighter than granite/quartzite), compressive strength 41–63 MPa, flexural strength 7–11 MPa, water absorption 8–11 % (markedly higher than hard rocks), Mohs hardness 3–4. Because of its siliceous quartz binder the stone is in principle acid-resistant — an important property that distinguishes Rainbow from many calcitic sandstones, which are acid-sensitive. Wine, lemon juice, vinegar or bathroom cleaners leave no direct etch marks as they would on marble or limestone. BUT: the high water absorption of 8–11 % is an essential aspect for the choice of material — under prolonged exposure to water or moisture, pigments can penetrate and cause discolouration. Careful sealing is mandatory.

At ROSSITTIS we carry Rainbow Sandstone as an unsized slab in 20, 30 and 60 mm thickness (from standard applications through to solid applications such as pool coping or solid stair treads), in tiles for floor and wall applications and for project-specific cutting. The available standard finish is honed C220 (a matt, finely rough grinding stage) — the typical treatment, and the one that suits the Rainbow appearance.

Compared with other multicoloured sandstones, Rainbow is one of the most expressive grades worldwide. Compared with the classic single-colour Red Main sandstone, Beige desert stone or the grey-blue Bavarian sandstone, Rainbow brings a dramatically livelier, more colourful composition. Within the Indian sandstone family, Rainbow differs markedly from uniform classics such as Modak (red), Mint (cream-green) or Kandla Grey through its multicoloured band structure. Teakwood Sandstone is related (with a similar wood-grain look, but dominated by brown and bronze), as is Mint Yellow (with a more uniform yellow tone). For architectural projects with a warm, lively material effect — prestige external façades, pool surrounds with a warm character, garden paths and patio areas, spa facilities, Asian- or Mediterranean-inspired architecture and buildings with a historic feel — Rainbow Sandstone is an exceptional and expressive choice. Important for planning: sandstones are not high-performance hard stones; for intensively used kitchen worktops, dense quartzites or granites are the more robust choice, while in wall, façade, external and garden applications Rainbow plays its exceptional visual strength to the full.

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 2.090 kg/m³

Druckfestigkeit 52,0 MPa

Biegezugfestigkeit 9,0 MPa

Wasseraufnahme 9,50 %

Säurebeständig Ja

Finishes

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

Geschliffen C220

Mattes Erscheinungsbild durch feinen Schliff mit Körnung C220 — die ebene Oberfläche wirkt ruhig, leichte Schleifspuren möglich. Im Vergleich zu poliert pflegeintensiver, dafür mit charaktervoller, naturhafter Anmutung. Wahl für Sandstein-Bodenflächen und Wandverkleidungen mit Wunsch nach mattmediterraner Wirkung.

Care & fabrication

As a Palaeozoic Indian sandstone, Rainbow Sandstone is markedly more maintenance-intensive than dense hard rocks such as granite or quartzite. With a Mohs hardness of 3–4 and above all with high water absorption (8–11 %), the stone requires deliberate care and consistent sealing. These points should be deliberately taken into account in the choice of material.

For interior applications we recommend very careful silane- or polysiloxane-based sealing at first installation, applied in two or three coats for sufficient penetration depth. The high water absorption requires a more intensive sealing strategy than with dense hard rocks. For interior applications we recommend refreshing every 2–3 years, and checking annually on floors or in heavily used 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. Because of the siliceous quartz binder, acidic cleaners are in principle unproblematic with Rainbow Sandstone (unlike with calcitic sandstones) — but they should nevertheless not be used regularly, because they can attack the sealer. Film-forming maintenance products and abrasive pads are to be avoided in every case.

Important: standing liquids, permanent moisture or strongly pigmented substances (red wine, tomato sauce, coffee, ink) can cause discolouration despite sealing — Rainbow Sandstone reacts markedly more sensitively to these than granite or quartzite. Prompt cleaning after spills is mandatory.

For kitchen worktops, Rainbow Sandstone is suitable only to a very limited extent — the high water absorption, the low Mohs hardness (3–4 = not fully cut- and scratch-resistant) and the sensitivity to strongly pigmented foods make it unsuitable for intensive professional kitchens. For designer kitchens with a deliberate material effect and a wabi-sabi approach the stone can work with very careful maintenance — assuming an honest set of expectations.

For external applications, Rainbow Sandstone is a very fitting choice when correctly planned. The surface finishes currently held in stock are listed in the »Finishes« block further down. Where there is direct exposure to water or moisture (pool coping, fountain elements, rain-exposed façades), particularly careful sealing is mandatory. In areas with frequent salt contact (de-icing salt, pool chlorine) we recommend an additional annual refresh of the sealer; Chinese and Indian sandstones sometimes react sensitively to freeze-thaw cycling with de-icing salt.

On frost resistance: Rainbow Sandstone has a relatively high water absorption — under freeze-thaw cycling in central Europe this can lead in the long term to fine surface splitting. Ahead of demanding external façades or floor applications with high frost exposure, we recommend a project-specific check of the data sheet with the importer and, where appropriate, the use of a water-repellent sealing system.

Frequently asked questions

How does the multicoloured effect in Rainbow Sandstone arise?

The multicoloured banding arises from different iron oxide and manganese mineralisations during the original sedimentation in a Palaeozoic shallow sea. Haematite (red iron oxide) produces the red and violet layers, limonite (hydrated iron oxide) the yellow and honey-coloured bands, manganese oxides the greenish and darker areas. The individual sedimentary layers were deposited over millions of years under changing conditions — hence the irregular, undulating band structure.

What is Rainbow Sandstone geologically?

Rainbow Sandstone is a Palaeozoic (roughly 540–250 million years old) fine-grained quartz sandstone from the district of Nagaur and the region around Jaipur in Rajasthan, northern India. The DNSA natural building stone database lists the material under identifier 4527. Petrographically the stone consists predominantly of fine-grained quartz with interstitial iron oxide mineralisations, which are responsible for the multicoloured effect.

What synonyms are there?

In international trade, Rainbow Sandstone also runs under the designations Jaipur Rainbow Sandstone, Rajasthan Rainbow, India Rainbow and Multicolor Sandstone. IMPORTANT: several independent stones share the trade name 'Rainbow' (including an Australian and a Chinese sandstone) — when ordering, we recommend always specifying the exact supplier and the origin (India/Rajasthan) in order to rule out confusion.

What technical values does Rainbow Sandstone have?

Typical sandstone values: bulk density 2,070–2,110 kg/m³, compressive strength 41–63 MPa, flexural strength 7–11 MPa, water absorption 8–11 % (relatively high), Mohs hardness 3–4. The stone is acid-resistant thanks to its siliceous quartz binder — a property that distinguishes Rainbow from calcitic sandstones.

Is Rainbow Sandstone suitable for kitchen worktops?

Suitable only to a very limited extent. At a Mohs hardness of 3–4, Rainbow is markedly more sensitive than granite or quartzite — it is not fully cut- and scratch-resistant and, given the high water absorption (8–11 %), absorbs pigments despite sealing. For intensively used professional kitchens we recommend alternative hard stones. For a designer kitchen with a deliberate material effect and a wabi-sabi approach, Rainbow Sandstone can work with very careful maintenance — with honest expectations about the formation of patina.

Is Rainbow Sandstone suitable for external use?

Yes, with several points to observe. A matt, textured surface finish is optimal for slip resistance. Ahead of demanding external applications with high frost exposure, we recommend a project-specific check of the frost resistance data sheet, because the high water absorption can lead in the long term to fine surface splitting under freeze-thaw cycling. In regions with salt exposure (de-icing salt, pool chlorine), an additional annual refresh of the sealer is sensible. With correct planning, Rainbow is particularly attractive for pool surrounds, garden paths, Asian- or Mediterranean-inflected external works and architecture with a historic feel.

How do I clean and care for Rainbow Sandstone?

Rainbow Sandstone requires deliberate care: first installation with a two- to three-coat silane or polysiloxane sealer, daily care with a pH-neutral natural stone cleaner and a microfibre cloth. Acidic cleaners are in principle compatible thanks to the siliceous quartz binder, but should not be used regularly. Refresh the sealer every 2–3 years (annually in heavily used areas). Respond immediately to strongly pigmented spills (red wine, tomato sauce, coffee, ink) — these can cause discolouration despite sealing.

Which finishes are available for Rainbow Sandstone?

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