Did I lose a diamond?

Walking along the beach in the dusk, I saw something sparkle for a moment .. excited to see it and find whether it was a treasure, I walk to it, pick it up..but that glint vanished, I rotate and move it to see on what was in it that glinted, on no discovery I put it back on the shore .. waves lap and move it side ways .. one last look behind and I felt that sparkle again, was it that I failed to remove the sand or did I fail to remove the shades adorned on my eyes..but by that time I had moved on .. Did I lose a diamond ?....