A piece of jewelry
worn on the ring finger
made of low-grade gold and Cubic Zirconium
that looks similar to an engagement
. Worn by unmarried women
(usually very attractive
or very smart
) on college campuses
informing many would-be suitors
they are not seeking a potential SO
These can be impossible to distinguish at a distance with the naked eye from real wedding or engagement rings as you have to talk to and get to know the female in a non-threatening way (very difficult as they can see a pending advance coming from a mile away).
This mind game tends to have a very high success rate on campuses (this is where my sister learned about the concept).