Ruby Pearl is my recently-adopted one-year-old Border-Collie/Jack Russell mix. About a month before I adopted her (and before I lost my two old dogs and was not planning to get a dog any time soon), I was reading the book Helter Skelter written by the prosecuting attorney for the Manson case. He described interviewing a witness at the ranch where the Manson Family hid out - a tough, seasoned horse wrangler named Ruby Pearl. Despite the dark tone of the book, she was an upstanding character and I thought to myself "wouldn't that make a great name for a dog?"
Little did I know I'd end up adopting a red-and-white little spitfire soon after, and I didn't consider many other names. Ruby by itself is not that uncommon, but I like the addition of 'Pearl'.
I blog about Ruby here: http://myrubicondays.blogspot.com/