mortar for limestone blocks

Quoted text begins.cementitious, render, harling, dry-hydrated lime, weatherings, quoins,
and fat lime. And how do you knock up the lime with water? It sounds
painful, and perverse.
End of quote.

Norman,

Some plastering terms here:
http://www.masonry-restoration.com/historic-stuccos.htm

Knocking up is the technical term for re-tempering plaster by adding water and
re-mixing. Knocking up replaces the free water lost through hydration of the
lime and by evaporation. Not recommended for Portland cement plaster because the
complex alumino-silicate crystals are broken up and not re-formed.

Simon