Porphyry quarries of Lessines

The Lessines porphyry quarries are exceptional for several reasons:

• Geologically unique: Porphyry is an exceptionally hard, durable igneous rock formed when magma solidifies underground—not on the surface as lava, but deep underground, making it very dense and strong. Lessines porphyry is considered a valuable building material, comparable in hardness and durability to granite.

• Rare quarrying in Western Europe: Porphyry quarries are rare in Western Europe. The site in Lessines is one of the major locations where this rock is extracted and is therefore considered exceptional. The quarry remains active today, while many other quarries in the region are closed. As a result, porphyry mining is still active in only a few locations in Belgium.

• Historical significance: Porphyry mining in Lessines began as early as the 15th century and reached its peak around the late 19th and early 20th centuries. For a time, the region was the center of porphyry mining and processing, employing thousands of people. Porphyry from Lessines was used, among other things, to make the famous Belgian cobblestones used in numerous cities in Belgium (and beyond).

• Cultural and architectural value: Lessines porphyry was used not only for paving (road construction, cobblestones) but also as decorative natural stone in monumental buildings (including the Our Lady with the Rose Hospital). The centuries-old ties with local architecture underscore the exceptional character of the quarry complex.

• Accessibility and heritage status: The Lessines quarries are one of the few places where you can observe the extraction, the typical stratification, and the old industrial landscape of porphyry mining. Some areas are protected as heritage sites or can be visited, further enhancing their uniqueness.

Pascal Brackman