If you believe that stones are actually the residue of the olive oil, you can easily prove it in a single flush, as suggested in Dyeing to know the answer by Andy:
"Next time you do a flush, add an extra ingredient: some harmless organic food coloring of a kind that is not affected by digestion, but is oil soluble and water soluble, and will color all ingredients: olive oil, juice, water mixed with Epsom salt.
Suppose you use red food coloring. Then when the stone-like objects come out, if they are truly from the liver/gallbladder, cutting them open with a knife should reveal that the stones have green or brown interiors but are green or stained on the outside with red. If they are red inside, they were formed in the intestine during digestion, and they are actually the residue of the olive oil/juice."
Upload you photos to CureZone Image Gallery for all of us to see the coloring inside stones.