Glass failure analysis expert performed a root cause failure analysis on a bottle failure. The cap on this bottle had not been removed. The failure analysis revealed a manufacturing defect on the bottle interior. On the upper left photo is a 30X photomicrograph of a portion of the origin on the fracture surface. The arrows show the travel direction of the crack exiting the origin. On the upper right is a 30X photonicrograph of the origin as it appears on the interior surface of the bottle. There is a “chip” associated with the origin; therefore, this is a product defect on the bottle interior.