Defect van de Maand

March, 2021
Egyptian necklace
Traditional necklaces of ancient Egypt incorporated parallel rows of beads, creating heavy concentric bands around the wearer’s neck. This image of a fracture origin presents a similar effect. Pronounced ripple markings on the fracture surface, such as those on this sample, are a hallmark of point contact damage. As the name suggests, point contact damage is caused by forceful contact with a hard, pointed object. This particular origin was found on the sealing surface of a bottle, and analysis via SEM-EDX revealed glass-to-glass damage nearby.
October, 2020
Flying Bug
This summer in Western Pennsylvania we have had to contend with mosquitos, flies, bees, hornets, and now these flying bugs. The bug-like inclusion shown here is a common crystalline devitrification stone called Beta Wollastonite. Wollastonite is composed of calcium silicate and will form in cooler areas of the furnace and forehearth. It typically crystallizes into large prisms that produce vivid retardation colors in polarized light.
September, 2020
This sea green stone actually started as a grass-green colorant. Chromic oxide, is a batch additive used to make green glass. It can form inclusions due to insufficient melting or mixing. Excessive moisture or humidity may have caused it to agglomerate. Chromic oxide stones are difficult to melt and therefore should not be returned to the cullet supply.
August, 2020
Nazca Desert Drawings
In the Kingdom of the Crystal Skull, Indiana Jones used (real) giant desert drawings to locate the (fictional) city of Akator. The unusual markings at the fracture origin shown here bear an eerie resemblance to the drawings created by the Nazcas, and are similarly shrouded in mystery. This particular origin was found at the inside knuckle of a glass container along with embedded material. Elemental analysis showed that the metal particulate was composed primarily of nickel and iron, likely caused by degradation of the plunger.
July, 2020
Bottle Opener
This crescent-shaped fracture typically occurs on bottles with a crown closure. Bottles broken during opening usually have a C-shaped fragment missing from the locking ring. This fracture pattern is usually caused when the consumer accidentally makes contact with the underside of the locking ring of the bottle with an opener rather than engaging just the cap.