It's hard to determine or pigeonhole just exactly what happened to this Pyrex. The white striations going up and down it appear at first to be on the outside of the glass. But when looking closely you can see that they are contained within the glass. Hard to determine this unless you're holding it in your hand. When looking at it through a magnifying glass, the white striations actually seem to be comprised and made up of not millions but zillions of ultra fine bubbles. You can see spots where they sort of fan out. Very strange Pyrex.