The process of pietra dura requires the use of an enormous range of colourful semi-precious stones and marbles sourced worldwide with many coming from Tuscany. Some marbles which were reused during the Renaissance from stone originally quarried by slaves of Imperial Rome are no longer available as the original quarries have been lost or closed but nevertheless Greenaway Mosaics have been able to collect a wide range of stones many of which are rare. The stones are sliced into a thickness of between 2 -5 mm (depending on the object being made) and then paper templates are made from the artwork for each piece of stone that is required for the design. The slice of stone and the area of the slice then has to be very carefully selected for its colour, shading and texture and the template is glued to the chosen area of the stone. The pieces have to be accurately cut out often by hand, following the template using a bow saw (archetto) with a plain taught iron wire. A moistened abrasive is applied to the wire to enable it to cut the stone. Alternatively for larger less intricate pieces a rotating diamond coated saw blade can be used. The pieces of stone are then very accurately filed by hand so that no daylight appears between adjoining pieces which are then glued together, carefully levelled & backed onto thin sheets of slate. The area of the marble background in which the pieces are to be inserted is carefully cut out and this calls for great precision. Finally after assembly has been completed the work has to be polished, usually by hand, with successive use of graded abrasive powders.   Preparing the design Selecting the stone (Lapis Lazuli) Slicing stones Individual pieces of paper are cut out of the design Natural glue of beeswax & pine resin is applied to the stone     Paper templates are stuck down to a carefully selected area of the stone Further glue is applied to act as a waterproof seal Traditional table vice A chestnut bow saw is used for cutting Carborundum is used to cut the stone with a smooth iron wire     Cutting around the template at a 30 degree angle Filing the edges to fit perfectly with the adjoining piece Fitting the two pieces together Gluing the pieces toegther face down in a 'v' groove The two pieces are now glued together     Matching finished pieces to an original panel Drilling holes to thread the iron wire through Sawing the Belgian black marble Cutting the black marble for the insertion of the pieces Part of a parrot to be inserted     Filing the aperture to be a perfect fit for the pieces Fitting the pieces without any gap Gluing the pieces in Polishing the panel using agate (a very hard stone) Finer grades of emery used with cork
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