by Jeffrey Appling GJG (GIA) Today we shape rock and gemstones using abrasive scraping techniques. Scraping and grinding are the same process of material removal. Hard material scraping away softer material. We grind material down into flat planes using a high speed rotating diamond impregnated discs or laps. Flat lap pictured below can make flat … More Sound Technology of our Ancient Ancestors Enables Internal Geometrics in Stone.