DURHAM, N.C. ? The ability to tell the difference between
crystals that formed naturally and those formed by human
activity can be important to archaeologists in the field. This
can be a crucial bit of information in determining the ancient
activities that took place at a site, yet archaeologists often
wait for months for the results of laboratory tests. Now,
however, an international team of physicists, archaeologists and
materials scientists has developed a process that can tell in a
matter of minutes the origin of samples thousands of years old.
The new device is easily portable and works by "lifting off" the
spectral fingerprint of a material with infrared light. The
first material tested was the mineral calcite, commonly found in
rocks such as limestone, which forms over millions years in
sediments. These rocks can also contain the mineralized shells
of sea creatures. Archaeological sites may also feature calcite
that was a part of ash, plaster, or other building materials. In
the latest issue of the jou