what are those small black bugs?

i just did a liver flush. I haven't done it in something like 3 years but this time was different.
I got about a table spoon of green small stones out and what's bothering me, about 20 tiny black bugs. They are only about 2 mm big, black, very hard, oval shaped and float.
I didn't dear to crush any of them but they remind me of some pests you get on garden plants. Are these eggs of parasites? I tried to to find images on google but didn't find any actual images, only drawings.

I have made photos and can upload also.
I thought maybe someone had experienced the same?