Researchers have determined what makes mollusk's shells so firm and transparent; the shells are clear enough to read through but extremely damage-resistant.
The shells are made from 99 percent calcite, which is extremely weak and brittle, a Massachusetts Institute of Technology (MIT) news release reported.
Many creatures have developed armor that can withstand multiple blows from predators, but very few of these shells are transparent.
Researchers exposed Placuna placenta mollusk shells to indentation tests using a diamond tip; they then used high-resolution analysis methods such as electron microscopy and diffraction the measure the level of damage inflicted.
The material was found to isolate damage using an "atomic-level process called 'twinning,'" the news release reported.
Twinning activates "a series of additional energy-dissipation mechanisms ... which preserve the mechanical and optical integrity of the surrounding material," the researchers said in the news release. This results in material that is 10 times better at "dissipating energy than the pure mineral," the news release reported.
These findings could have both military and commercial applications. It could be used to create protective shields for soldiers' eyes and even create effective blast shields.
"[It is] an excellent and elegant piece of work." He says it "successfully demonstrates the effectiveness of nanoscale deformation twins in energy dissipation in bioceramics, and should be able to inspire and guide the development of manmade ceramic materials," Huajian Gao, a professor of engineering at Brown University who was not involved in the research, said in the news release.
"As a first-of-its-kind [demonstration of] the effectiveness of deformation twins in natural materials, this work should have huge practical impact," Gao said.
"The work was supported by the National Science Foundation; the U.S. Army Research Office through the MIT Institute for Soldier Nanotechnologies; the National Security Science and Engineering Faculty Fellowships Program; and the Office of the Assistant Secretary of Defense for Research and Engineering," the news release reported.
