Inspired by the tough exterior of grapefruit and fragment-resistant mollusks, engineers from Durham University, U.K., and Fraunhofer Institute for Machine Tools and Forming Technology IWU in Chemnitz in Germany, have developed a new material that cannot be cut with machine tools.

The patent-pending material, called Proteus — in a nod to the shape-shifting mythical god — is composed of ceramic spheres enveloped in a cellular aluminum structure. According to developers who call it the first of its kind, the material is light, strong and non-cuttable.

During its development, the engineers discovered that the material could not be cut by machine tools such as drills, angle grinders or high-pressure water jets. Instead, vibrations within the ceramic spheres blunted and eroded the drills and angle grinders.

Reportedly, the ceramics fragmented into fine particles, thereby filling the cellular structure of the material and hardening in response to the increased speed of the cutting tool, thwarting both drilling and cutting attempts.

Additionally, high-pressure water jets were also unsuccessful due to the material’s curved construction, which widened the water jet stream, consequently reducing the water jet’s cutting power.

According to the engineers, the material could one day be used in products like armor, bike locks and protective equipment worn by those working with dangerous machinery.

The research appears in the journal Scientific Reports.

For more information on the material, watch the accompanying video that appears courtesy of Durham University.