Someone (or something) that has hidden exceptional characteristics and/or future potential, but currently lacks the final touches that would make them (or it) truly stand out from the crowd.

The phrase is metaphorical and relates to the fact that naturally occurring diamonds are quite ordinary at first glance, and that their true beauty as jewels is only realized through the cutting and polishing process.

Nominate someone that you think has true potential to be one of Anguilla diamonds, we will cut and polish her to be the diamond that you know she can be.

This is going to be a short live contest, it starts now and ends on the 24th.