Orwell Clunch (England, UK)

Orwell Clunch - Orwell Clunch Pit, Orwell, Royston, Cambridgeshire, England, UK

The Orwell Clunch Pit is a site of Special Scientific Interest (SSSI), known for exposing the Upper Cretaceous Chalk. "Clunch" is a traditional English term for a harder, more durable variety of chalk often used as a building material in East Anglian churches and cottages. Here we are dealing with pure Cretaceous Chalk, or "Clunch." This material is a specific, hardened variety of limestone composed almost entirely of the microscopic skeletal remains of coccolithophores (ancient marine algae). Unlike the soft, crumbly writing chalk most people are familiar with, clunch is a more consolidated, "blocky" rock that has been a vital building stone in East Anglia for centuries. These specimens represent the compressed, 85-million-year-old seafloor of the Santonian age, free of the silica nodules that often characterise the wider region.

This specimen shows the classic "blocky" fracture of high-quality clunch. It features a clean, off-white colour and a remarkably fine-grained texture that feels smooth and almost powdery to the touch. This piece highlights the structural integrity that made clunch a popular choice for carved architectural details in local churches. You can see the subtle bedding planes where layers of marine sediment settled in a calm, deep-sea environment. Its value lies in its purity as a representative sample of the Upper Chalk Formation, providing a perfect tactile example of a biogenic sedimentary rock.

Origin: Orwell Clunch Pit, Orwell, Royston, Cambridgeshire, England, UK
Rock type: Clunch / Chalk
Size: ~5-7(L) x 6(H) x 5(W) cm (see scale cube), 250 g