Bath stone alternative: Duna and Perla
Bath stone is the cream limestone the city of Bath was built with. It is oolitic, made of spherical carbonate grains the size of sand, and can be sawn and carved in more than one direction. Duna and Perla are sandstones, a stone of a different family, and come close to it in colour: Perla to the cream of the freshly cut limestone and Duna to the honey it can take on outdoors. In compression and in bending, the loads a piece carries before it breaks, they give 73 and 8.5 MPa; the BRE datasheets for Bath stone run from 14 to 29 and from 3.4 to 5.4.
Bath stone
- Type:
- Middle Jurassic oolitic limestone (Great Oolite)
- Origin:
- Around Bath, in Somerset and Wiltshire (UK)
- Colour:
- Cream when freshly cut; it can weather towards honey
Bath stone is still in production, mostly from underground mines around Corsham and Limpley Stoke, along with an open quarry at Combe Down. The alternative answers a different need. New-build work sometimes wants that cream or that honey on pieces that are walked on, work in bending or take a lot of rain, and there the BRE datasheets for the limestone recommend detailing that protects it from water.
Perla
Perlatto cream calcareous sandstone. We propose it when the reference is freshly cut Bath stone; its test values are identical to those of Duna.
View stone
Duna
Calcareous sandstone from our quarry, tan in colour with orange hues. We propose it when the tone to follow is that of Bath stone after years outdoors.
View stoneTechnical comparison
| Property | Bath stone | Perla · Duna |
|---|---|---|
| Petrographic family | Oolitic limestone (Great Oolite, Middle Jurassic) | Calcarenite (calcareous sandstone), both |
| These are different families. The equivalence proposed is one of colour and use. | ||
| Colour | Cream when freshly cut; it can turn honey after years outdoors | Perlatto cream · Tan with orange hues |
| Apparent density | 1,980 to 2,250 kg/m³ (published data) | 2,410 · 2,410 kg/m³ |
| Compressive strength | 14 to 29 MPa depending on the mine and the bed | 73 · 73 MPa |
| The Bath stone ranges come from five BRE datasheets, with tests from 1996 and 1997 on six beds from five workings. | ||
| Flexural strength | 3.4 to 5.4 MPa | 8.5 · 8.5 MPa |
| Freeze-thaw | Test not determined on the five BRE datasheets | Bending from 8.5 to 7.9 MPa after 56 cycles |
| With no frost figure for the limestone, this row allows no comparison. | ||
| Porosity / water absorption | 17 to 27 % porosity; 6 to 12 % absorption by weight | 12.6 % open porosity |
| The comparison is made on porosity, because the Duna and Perla datasheet gives no absorption by weight. | ||
| Abrasion | 26 to 35 mm | 25 · 25 mm |
| The lower the figure, the less wear. BRE places stone for heavy traffic below 23 mm, so all three are for pedestrian use. | ||
| Slip resistance | 73 to 84 on the four datasheets that test it | 94 dry, 78 wet (SRV) |
| The BRE datasheets give a single pendulum value, without stating whether dry or wet, and regard stone above 40 as safe. | ||
| Finishes | Sawn ashlar and carved or moulded pieces | Perla and Duna: sawn, honed, sandblasted, bush-hammered (also fine and coarse), brushed, chiselled, split and Rubio's Special; neither takes a flamed finish |
| Supply | Limestone in production, mostly from underground mines in Wiltshire | Sandstone from our quarry in Lleida, worked at our own factory |
Equivalence sheet (PDF)
This comparison on one page, with the technical data and sources, to share with your team or client.
Duna and Perla are a colour alternative to Bath stone and belong to a different family of stone. We propose them for new-build work and public realm where that cream or that honey is wanted with more mechanical strength and less porosity. To repair or extend a listed building, or any historic masonry where the new stone has to marry with the original in grain and behaviour, the option is Bath stone itself, which still comes out of its mines.
One limestone and two sandstones
Bath stone comes from the Great Oolite, a Middle Jurassic formation, and shares its Jurassic age and oolitic grain with Cotswold limestone. It owes its strength to the crystalline calcite cement that binds the grains. Duna and Perla are calcarenites, the name given to calcareous sandstones, and come from our quarry in Lleida. With the samples side by side, the grain and the texture are different. The likeness lies in the colour, which is why we propose them for new-build work, on facades, walling and paving that want the Bath tone without the stone having to be the same. Repairing a historic building follows another criterion. Historic England recommends replacement stone that matches the original as closely as possible, and that calls for a limestone from the same formation.
Bath stone against Duna and Perla on test
Compressive strength tells how much load a piece takes before crushing; flexural strength, how much it takes when supported at two points, like a flag or a lintel. BRE, the British building research institute, tested stone from five Bath workings between 1996 and 1997: compression runs from 14 to 29 MPa, bending from 3.4 to 5.4 MPa and porosity, the volume of voids that water can fill, from 17 to 27 %. The values for Duna and for Perla are 73 MPa, 8.5 MPa and 12.6 %. In abrasion wear the gap is small, 25 mm against 26 to 35, and BRE keeps heavy traffic for stones below 23. On the pendulum, which measures surface grip, the limestone scores between 73 and 84 and BRE regards any figure above 40 as safe; Duna and Perla give 94 dry and 78 wet. None of those datasheets includes the frost test. Duna and Perla go from 8.5 to 7.9 MPa in bending after 56 freeze-thaw cycles.
Perla for the cream, Duna for the honey
Freshly cut, Bath stone is cream in colour; with years outdoors it can take on honey tones. Perla, perlatto cream, is the option when the reference is the new limestone. We recommend it for facades and large-format pieces, such as the bush-hammered ones of up to 2.40 × 1 m on the Hotel ME in Barcelona, and for pool copings. Duna, a tan stone with orange hues, is closer to the limestone once weathered. We recommend it for facades, arches and structural elements, setts and outdoor paving. In London its setts are part of the paving in the Greenwich Park restoration, completed in 2024, and the facade of Barcelona’s Hotel Universal was built in Duna because it resembles Montjuïc stone, which was no longer being quarried.
Frequently asked questions
Can Duna or Perla be used to restore a Bath stone building?
We do not propose them for that. Historic masonry is repaired with stone that marries with the original in composition and behaviour, and Duna and Perla are sandstones. Their place is new-build work that wants the Bath colour.
Is Bath stone a limestone or a sandstone?
It is a limestone, oolitic and Middle Jurassic, made of small spherical carbonate grains. Duna and Perla are sandstones, calcareous ones, from our quarry in Lleida. They coincide with it in the colour range, from cream to honey.
Which of the two comes closer to the Bath colour?
It depends on the reference. Perla, perlatto cream, comes close to the freshly cut limestone; Duna, tan, to stone that has spent years outdoors. The reliable way is to compare the sample with your stone.
Can they be used for outdoor paving?
Yes, for pedestrian paving. Both give 25 mm in abrasion and a wet pendulum of 78, well above the 36 that marks low slip risk. For carriageways with vehicles we have Northcliff Blue.
How do they respond to frost?
The test puts the stone through 56 freeze-thaw cycles. At the end, the bending strength of Duna and of Perla is 7.9 MPa against the initial 8.5, 7 % less. The BRE datasheets for Bath stone do not include that test, so there is no figure for the limestone to compare it with.
Related comparisons
All eight Rubio sandstones, their test data and the other published comparisons, on one page.
Spanish sandstone for UK projectsCheck availability and lead time
Tell us which piece you need and which Bath tone you have in front of you, the new cream or the weathered honey, with a photo if you have one. We will send a sample of Perla or of Duna, and of both when the reference sits between the two.
- Availability, lead time and price with your measurements
- Physical sample free of charge for professionals
- Technical datasheet with test values