The term ‘coloured stones’ refers to all gems with the exception of diamonds.
The cutting of coloured stones is called lapidary work.
The cutter is known as a lapidary or faceter.
The cutter must take into consideration how to get the best characteristics out of the stone, such as depth of colour, pleochroism ( different colours viewed at different angles in the stone), and to get a good sized finished gem by sometimes following the shape of the rough stone.

Transparent stones, once roughly shaped, are faceted on horizontal grinding wheels. The stone is cemented onto the end of a metal stick, usually 10-15 cm long, called dops. The dops are guided at an angle related to the facet being cut, following a set pattern of selected angles.

The horizontal cutting disc can be made from lead, bronze, copper, tin etc and the polishing powders sprayed on can be carborundum, diamond or titanium carbine.

Mining for sapphires in QLD
A day at the mine

Lou is in a new hole about 7 foot deep to the floor, we have had good stone from here, Lou is fairly excited as he is getting closer to an old tunnel dug before the flood cave in.

This area produced around 100-200 carats of sapphire per day for a couple of months and we were looking forward to getting back to this area eventually.

Now the dirt is looking very good, heavy black broken ironstone with white bits of clay and green rocks. The old timers say you are on the sapphire when your wash has salt pepper and chives – the black broken ironstone - white ash / clay - green floor/arsenic rocks (don’t put these in your mouth).

So Lou has been jack hammering this morning to loosen the dirt, he shovels it into buckets and then winches them to the surface.

Since we are working away from the machine and open cutting this hole, it is easier to winch to the surface. The buckets are lined up, ready to be put through the machine.

Read the entire day at the mine article.
Where to look for sapphires