Laser Drilled Diamond. The Drill Channels you See are Not All Individual Channels, for the Most Part, They are Reflections.
Image Courtesy of Conny Forsberg, FGA.
A laser is used to create a tiny channel from the surface of the gem to an inclusion. Acids are then used to either bleach or remove the inclusion, thus enhancing the diamonds’ clarity. The drill hole may or may not be filled after the removal of the inclusion has been completed.
Identification shouldn’t be too much of a problem, proper inspection with a microscope should do the trick. Note that even melée sized diamonds can be drilled so don’t just investigate the center stone of an item!