Reigate Stone

rdf:langString Reigate Stone

rdf:langString Reigate Stone is a freestone that was mined from the Upper Greensand in north east Surrey. It was used in building work throughout the middle ages and early modern period. It is sometimes classified as a calcareous sandstone, although very little of the silica content is in the form of detrital sand grains. In addition to silicon dioxide, the stone also includes clay, fine-grained calcite, mica flakes and glauconite. Since exposure of Upper Greensand is rare, Reigate Stone was generally extracted from underground workings, although it may have been quarried from the surface at first. The stone was mined using the post-and-stall technique, in which adits (approximately 4 m (13 ft) wide and 1.5 m (5 ft) high) were cut into the beds, which dip downwards below the chalk above. Parallel grooves in the floors of these workings suggest that cut stone was brought to the surface on wooden sledges. Mines are thought to have existed along the base of the North Downs from Buckland in the west to Chaldon in the east. Many probable sites were most likely destroyed by the construction of the M25 motorway, although the earliest recorded mine has been identified at the foot of Colley Hill to the north of Reigate.