Now, playing again with the digital camera and some hydrochloric acid, I've put some of the previously photographed "pebbles" (more grit and grains of sand) in the HCL solution to see which dissolve and which survive. Those that survive - intact - are presumably diamonds...
This is the starting photograph:
You can see the bubbles as the HCL works it's magic. I spilled a bit, always, hopefully the desk and computer are here in the morning, but a time-lapse animation/.gif/vine will help to show me where to steer my attentions...In the past, I never knew which ones "survived" and which ones merely shrunk, and needed more acid to disappear. Now I'll know...