What is this close-up picture? (WotsThat: Gravel stone texture (macro))

Question

What object is shown in this zoomed-in close-up photo?

BasaltDrifter · Accepted Answer

Gravel stone texture (macro). Gravel is defined by particle size rather than by what rock it's made from, so it can be crushed granite, limestone or almost any rock, as long as the pieces fall between about 2 and 64 millimetres across.

Answer: Gravel stone texture (macro)

More mineral close-ups