Once mined most are then passed to a gem cutter who's job it is to bring the gemstone to life. Gem cutters are artists, craftspeople with a very accurate eye for detail. Before cutting some sapphires may be picked out for heat treating. These are normally gems that have a lot of rutile inside them. Rutile is another crystal that can grown inside the sapphire crystal and can cause the sapphire to look overly dark and unappealing. Heat treating can dissolve the rutile in much the same way as nature did back when the gems were created in lava flows. If heat treating is to occur its normally the gem cutters keen eye that makes the decision and carries out the procedure. Heat treatment of Australian sapphires is rare as most dont require it. In some parts of the world like Sri Lanka and Montana in the USA its a routine procedure carried out to about 95% of all sapphires mined. When cutting the gemstones simple but very precise tools are used that have not changed significantly inhundreds of years. They use a spinning disk covered in different grades of diamond dust and an arm that holds the gemstone on specific angles set by the gem cutter. There are many standard patterns that are used, the patten chosen will generally be determined by the shape of the rough gemstone.