Jade can be unforgiving to drill, especially when the hole is small or the piece has internal variations. In my experience, the drill specification matters as much as the diamond itself. Grit size, bond type, wall thickness, coolant, and feed pressure all affect drilling speed and the risk of chipping or overheating.
For smaller jewelry or lapidary holes, I usually prefer a diamond drill with a controlled feed and plenty of cooling rather than trying to force the tool through the material. A rigid setup also makes a noticeable difference in hole accuracy.
This reference on diamond drill for jade covers different diamond core drill options for jade and other hard lapidary materials.
What drill diameter and grit combination have worked best for you when drilling jade?