Terminology index:

D

• dacite

  a fine-grained, extrusive (volcanic) rock, intermediate in color and composition between basalt and rhyolite
  
  

• damp-proofing

  one or more coatings of a compound that is impervious to water applied to a surface above grade.
  
  

• defect

  those features which affect or have the potential of affecting the structural soundness of building stone, or may affect the durability of the building stone. Sometimes used for visual features such as xenoliths or veins.
  
  

• dentil

  block projections on an entablature.
  
  

• dentil course

  the lower part of the cornice with dentils. The cornice is jointed to allow machines production of the dentils.
  
  

• dentils

  small, rectangular blocks under a classical cornice, resembling a row of teeth.
  
  

• dimension stone

  quarried stones, generally two feet or more square, of a specified thickness. Usually with one or more mechanically dressed surfaces.
  
  

• dolomitic limestone

  a limestone rich in magnesium carbonate, frequently somewhat crystalline in character, found in ledge formations in a wide variety of color tones and textures. Generally speaking, its crushing and tensile strengths are greater than the oolitic limestones and its appearance shows greater variety in texture.
  
  

• dowel

  a short piece of non-ferrous metal or slate fixed into a mortise or sinking in the joints of adjoining stones to prevent movement.
  
  

• dressed or hand-dressed

  the cutting of rough chunks of stone by hand to create a square or rectangular shape. A stone which is sold as dressed stone generally refers to stone ready for installation. Sometimes called scabbling.
  
  

• drip

  a recess cut beneath and slightly behind projecting stone to prevent water from running down the face of the wall below.
  
  

• dripstone

  a projecting moulding over the heads of doorways, windows and archways to throw off the rain. Also known as a "hoodmould" and, when rectangular, as a "label".
  
  

• dry

  an open or unhealed joint plane not filled with calcite and not structurally sound.
  
  

• dry wall

  a dry wall is a stone wall that is constructed one stone upon the other without the use of any mortar. Generally used for retaining walls.
  
  

• durability

  the measure of the ability of natural building stone to endure and to maintain its essential and distinctive characteristics of strength, resistance to decay, and appearance, with relation to a specific manner, purpose, and environment of use.