Every step in special lapidary techniques is vital from the choice of the slab, the trim sawing to the final polish. But potentially the most vital is the original coarse grinding stage. This is where you may be making calls on the bezel, curve, table, girdle and the general shape you need your stone.
When using polishing agents, technique and speed are significant. Decide what process you're going to use like leather, canvas, felt: Linde A, tin oxide, cerium oxide.
Belt Sander
Also take care with the heat buildup, it's critical to have an even distribution. Some stones transfer heat uniformly, but it's best to dodge any unexpected thermal shock, keep it moving and bring it up slowly.
The following are some special lapidary techniques:
Sawing - a thin circular blade made from steel, copper or phosphor bronze alloy infused on the outside edge with diamond grit and rotating at several thousand surface feet per minute scratches its way through a stone. Oil or water is used to wash away the waste and keeps the stone and the saw blade from overheating.
There are various sizes of circular saw - routinely sixteen to twenty-four inches in diameter for stones that are 1/8 to 3/8 in. thick. A six to ten inch in diameter for smaller stones. There are jigsaws that are great for cutting curved lines.
Grinding - this is done with silicon carbide or diamond-infused wheels. These are used to shape the gemstones to the coarse form called preform. Water and oil is used to wash away the waste and avoid overheating. Coarse diamond or silicon carbide like sixty grit or 100 grit is employed for fast removal of stone and the finer abrasive (600 or 1200 grit) is utilized for the final shaping and sanding.
Sanding - This has similarities to grinding but it utilizes the finer grits. This takes away the deep scratches left by the harder abrasives. As this step isn't done as quick it permits more control when getting the final shape of the stone prepared for polishing. A belt sander is utilized with stones that have round surfaces as they avoid making flat areas and inspire smooth curves.
Lapping - is both like grinding and sanding, with the exception that it is done on one side of a rotating or vibrating flat disk called a lap. This is used to make flat surfaces on a stone. Laps are made from steel, cast-iron or copper-bronze alloy.
Polishing - when you have the stone sawed and ground to the shape you would like and have removed any coarse marks, it is then polished which assists the light to reflect on the surface of the stone. Grades of 50,000 to 100,000 diamond mesh are used to shine materials. There also are metal oxides that may be used to shine stones as well like: aluminum, cerium, tin, chromium, ferric oxides, or silicon dioxide.
Stones differ when it comes to the simplicity of polishing and you may be quite creative when using polishing agents and surfaces. For flat surfaces you may use tin, tin-lead, lead, leather, felt, pellon, wood or Lucite laps. For round surfaces polish on felt, leather, cork, fabric or wood.
Drilling - when you would like to drill a hole through a gemstone you want a little rotating rod or tube with a diamond end of silicon carbide and coolant. Vibrating or ultrasonic drills are also great but these are pricey.
These are just a few of the special lapidary techniques, there's a lot of info available online and they're going to give you recommendation and tips when using these techniques.
