© Geoff Downer 2019
Basics
Geology: Fine-grained white limestone
Age: Middle Jurassic
Provenance: Aubigny, Normandy
Where to see examples
There are no known examples at ground level.
Description
Aubigny stone is a Jurassic limestone from Normandy in France. It is described as fine-grained and having similar characteristics to Portland Stone and is quoted in some texts as D’Aubigny and sometimes referred to as O’Beaney. The stone was quarried underground between the villages of St Pierre Canivet and Aubigny in the Department of Calvados. The stone beds are of the same age as Caen Stone and the quarries are located about 30km SSE of Caen. The stone was first used in the fourteenth century and the underground quarries are reported as having closed in the 1970s.
The more crystalline, denser and harder nature of the stone made it suitable for stairs and steps and also for exterior work where weathering was likely to be more intensive. During the late nineteenth and early twentieth century restorations of the cathedral Aubigny Stone was used in the external base of the south-west transept, the parapets of the Bell Harry Tower and in a number of stringcourses on the south side of the cathedral. Unfortunately its use has not proved popular with recent conservators, as the stone’s permeability differs significantly from that of other stones in the cathedral walls. The result has been that migrating pore waters have met the impermeable Aubigny Stone and consequently created a build-up of water near the surface of the neighbouring stones. Consequential frost damage and the release of salts from solution at this juncture have both severely weathered the adjacent blocks of stone.
Much black limestone was quarried from the district around the city of Tournai, hence the name often given to the stone: Tournai Marble. The term touchstone derives from goldsmiths testing for the purity of gold by rubbing a sample against the fine-grained, black limestone and observing the colour of the streak left on the stone surface.