Timber and minerals adjustments and hard stones for decoration and collection of gems the size and needs of cleaving which are essential for sawing the lapidaries to eliminate most of the parts unfit for gems. For centuries the world of lapidary / clivaient diamond gems with a "corner" and blunt force to separate the parties and best qualities unfit. Of the gem cemented on its support, have little choice then be eligible for the craftsman to a final form of the selection of parts cleaved. Since then, modernity allows less risk of damage and loss using Diamond saw and thickness of disks of a few tenths of millimeters of cut gems safely, with a loss minimized. The selection and choice of cut after examination of the gem becomes more simple and comforting to the tailor and reassured. Holes means of forests with hollow diamond cores also allow ejection of achievements with multiple constraints that must speeds beings measured according to the nature of gems and depth of holes to run. In recent years the use of ultra-sounds allows by means of a generator to carry out mass bores of a few millimeters to several centimeters, by vibration of the particulate matter by means of abrasive agent such as silicon carbide. Not safe for users, it remains important to protect it in the best sounds generated by protection desirable.