A quick vinegar test on a 'petrified wood' piece from Arizona went badly wrong

Emma Clark · 2026-04-04T02:45:05.601802+00:00

I bought a nice looking specimen at a shop in Sedona last month, labeled as petrified wood. I wanted to check for calcite, so I put a single drop of white vinegar on a small corner. It didn't just fizz a little, it started a fast reaction and left a permanent white crust spot about the size of a dime. I think the piece might have been treated with a sealant or something. Has anyone else had a simple test ruin a sample because of an unknown coating?

morgan.jason6mo ago

I did the exact same thing to a piece of Utah agate I thought was rough. One tiny drop of vinegar and it looked like a science fair volcano erupted on it. Turns out the seller had dipped the whole thing in some kind of wax. I felt like a total genius.

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eva_moore6mo ago

I used to think a vinegar test was harmless, but that "science fair volcano" result changed my mind fast.

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dereks116mo ago

Try testing on the underside first, it often avoids any coatings.

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