An introduction to lime - The Hempcrete Topic: Designing and Building with Hemp-lime - page 53

'Knocking up' a pre-mixed lime putty plaster to a workable
consistency before use.
The limes just described, which set with carbonation in the presence of air, are usually pro-
duced from seams of limestone that are very pure, containing a high level of calcium and
few impurities in the form of clay materials. This pure form of limestone deposit is the
most common type found in the geology of the British Isles.