by Kelly Rectenwald, Objects Conservator
In the museum’s conservation lab, I’m working on small archaeological finds. Several small copper alloy objects, pieces of jewelry and articles of adornment, are all showing signs of bronze disease. This specific type of corrosion is normally caused by contact with salts and water in the soil of the burial environment. It presents itself as a bright blue powder that erupts from the surface of the object, often spilling out of cracks beneath more stable forms of corrosion.
Unfortunately, bronze disease will consume the metal core of an object leaving behind nothing but a pile of powder. To prevent this and preserve the objects, all the burial dirt and corrosion must be removed from the surface before the entire object is sealed with a conservation grade adhesive that prevents future deterioration. This process often reveals details of the original surface; in this microscope photo of a scarab ring, you can see a detail of a small, cleaned area of the metal wire band where burial dirt and corrosion have been removed to reveal a decorative coiling of the wire.
Once treatment is complete these objects will not only be stable, but many of their beautiful details will once again be visible.
Microscope image of an ancient scarab ring. The removal of corrosion and burial dirt in the center revealed a metal coil around the ring’s band.
Scarab Jewelry, 945– 15 BCE, Dynasty XXII, Abydos, Egypt, copper alloy wire band with faience scarab, Gift of the Egypt Exploration Society, 1912.379