Terminology index:

L

• lava

  a general term applied to igneous rocks, such as basalt and rhyolite, that erupted from the earth by volcanic action.
  
  

• lead buttons

  lead spacers in the solid horizontal joints to support the top stone until the mortar has set.
  
  

• lewis bolt

  a tapered head wedged in a tapered recess in stone for hanging soffit stones.
  
  

• lewis holes

  holes in cut stone for lifting and support during setting of cut stones and sometimes for permanent support. Holes are checked for the particular Lewis lifting device or hook to be used.
  
  

• limestone

  a sedimentary rock composed of calcium carbonate; includes many varieties. (See oolitic limestone, dolomitic limestone, crystalline limestone). Limestones that contain not more than five per cent magnesium carbonate may be termed calcite limestone, as distinguished from those that contain between five and 40 per cent magnesium carbonate (magnesium or dolomitic limestone), and from those that contain in excess of 40 per cent as the mineral dolomite (dolostone, formerly known as the rock dolomite). Recrystallized limestones and compact, dense, relatively pure microcrystalline varieties that are capable of taking a polish are included in commercial marbles.
  
  

• liners

  strengthening elements attached to the back of stone slabs, usually a structurally sound section of similar stone dowelled and epoxied into place.
  
  

• lintel

  the block of stone spanning the top of an opening such as a doorway or window; sometimes called a head.
  
  

• lipping

  usually refers to flagging materials; caused when two pieces of material to be joined together are slightly warped or twisted causing one or more edges to be higher or lower than the adjoining material.
  
  

• lug sill

  a stone sill set into the jambs on each side of masonry openings.