What are the rules and traditions surrounding Mourning Pins?

by jrteeter

I saw an image of mourning pins. I wanted to find out when it became en vogue for pins to be black so as to further designate that someone is in mourning. And if anyone knows anything about the company that made this particular brand that would be great. http://imgur.com/ODjxSW1

KNHaw

To clarify, are these pins from Europe/England or the US?