Types of flint

There are two main types of flint, field flint and quarried flint. Quarried flint is usually of a higher quality than field flint. It is this flint which is knapped. Knapping involves lumps of quarried flint being struck once with a large hammer to break the stone. It is carried out purely for decorative purposes to reveal the core of the flint and its colour. This can be grey, black or white with a cortex – a line of chalk around the perimeter. The latter is considered the best quality and is found in Norfolk. Quarried flint is used in more intricate projects, such as flush work panels on buildings or more decorative walls. Flush work involves panels of stone cut to shape with the spaces between filled with knapped or squared flints. Lynn is using field flint to restore the boundary wall. This is literally found on the surface in fields, in pieces ranging from small stones of 2-3in (5-7cm) in size to large rocks 12in (30cm) long. This type of flint can be rough and dry. Exposure to frost after the stones have lain in fields for hundreds of year causes fissures and cracks. This means the flint cannot be knapped as it will break in the wrong place. The colour of field flint ranges from whitish grey to orange, depending on the natural geology of where it is found. “During the 18th and 19th centuries, women and children were employed to remove the flint from fields where the ploughs kept hitting it,” says Lynn. He uses the flint already at a job, but if he needs more, he sources it himself from a field in the area.