Hm. It seems like the intention is that you can send a few diamonds to anyone who claims, in your faction chat. Using it opens the faction chat window, so that’s probably relevant. Somewhat like how people in cross-server auction all get amethyst spread between them. However, it doesn’t seem to work yet, and the send button doesn’t do anything. Some others from S3 also experienced that error.
You probably aren’t missing out on anything at the moment, unless someone’s figured out some convoluted way to make it work. I haven’t seen it used, however.