Scientists at Hitachi Research Labs in Japan have devised the smallest radio-frequency identification (RFID) tag ever, just 0.05 millimeter by 0.05 millimeter, tinier than a grain of sand or a pepper flake, Popular Science magazine reports.

The so-called powder chip is thin enough that it can be mixed with paper pulp to add a layer of counterfeit protection, the magazine reports. It has caught the interest of the jewelry industry, which could invisibly embed the chip in rings and necklaces to track their origins, making them more difficult to sell illegally.

Each chip stores a unique 38-digit ID number, the magazine reports. When stimulated by an RFID reader, the chip emits its code, verifying its identity. The code is integrated into the chip’s circuitry, making counterfeiting impossible.

Hitachi unveiled the chip in February and plans to take it to market in 2009, the magazine reports. Wal-Mart might be one of the first retailers to debut the radio dust.

JCK