Last year at SIHH Cartier unveiled the Rotonde de Cartier with turtle motif and the response from clients was extremely positive - the 10 pieces sold out in a flash. So for 2012 a mosaic technique was used for the Santos Dumont in white gold, though with a twist.

Before the pieces of the mosaic are put in place, however, the dial begins with the white gold base. The neck, mane and nose of the horse are hand-engraved solid gold, while the rest of the animal is outlined in gold as well.

Aside from the gold framed horse, the Santos Dumont with horse motif, however, also differs from last year's turtle mosaic in its mosaic technique. Unlike the turtle, which was composed entirely of tiny cubes to form the motif, the horse is executed with two different styles of mosaic.

The horse itself is comprised of irregular tesserae cut from cacholong (a form of opal), while the background is a mosaic made of tiny squares - each a fraction of a millemetre in size - in earth jasper, Kalahari jasper, grey Madagascar jasper and chocolate obsidian. In total, 400 tiny pieces of semi-precious stone are used for the entire dial.

Each of the 400 pieces starts with the right piece of stone that is selected for its colour, and then polished down to the right thickness. Subsequently each piece of the square mosaic pieces is cut by a machine that engraves a network of parallel lines both horizontally and vertically to create a checkboard grid on the piece of stone.

Individual squares are then broken off one by one for the dial mosaic. But because not every tile of the background mosaic is square, some of the pieces have to be cut with a tiny saw. Once the motif is formed, the spaces in between the stones are filled with cement.

120 hours of work is needed to complete each Santos Dumont, 50 hours to finish the horse with the tesserae and another 70 hours to assemble the miniscule pieces of the background.

Only 40 of these will be made in white gold, and an additional 10 with baguette diamonds.

- SJX