Industrial-grade diamond drill bits are a relatively new advancement in stone cutting technology, making cleaner, sharper and more intricate facets widely available. These mathematically precise cuts are more consistent than humans could ever craft by hand, thus providing us with an opportunity for mass-produced, identical stone beads at a remarkably low price point.
The precision of the cut is not the only reward when diamond-cutting stones. With the use of geometry and a good understanding of light, which is extremely important for precious stones with strong dispersion, we can create optimal cuts for each individual stone type. The facets on each stone become nearly to perfectly flat, with minimal or no need for polishing. Diamond-cut stones generally sparkle better, even in stone types where you don't typically see it, like some jasper varieties.
We can also now get extremely small beads and stones showing the same luster and shine as larger stones. These stones work well when paired with larger beads as sparkling accents, but also shine alone on small, delicate crafts.