It was published several times before he got his job at cracked.com. First it was a collection of stories he wrote for Halloween over several years on his blog pointlesswasteoftime.com, then he self-published, then it was published by Permuted Press (a small horror publisher), and finally Thomas Dunne.
Not glass, but hardened resin. Used to track littoral currents and drift. Has metal so it can be found later with a metal detector.