Did you know that of all of the rocks in the world, there are only 3 main kinds? What are they? And how can you tell them apart? Jessi and Squeaks show you how you can become a rock detective! ---------- Like SciShow? Want to help support us, and also get things to put on your walls, cover your torso and hold your liquids? Check out our awesome products over at DFTBA Records: http://dftba.com/SciShow Or help support us by becoming our patron on Patreon: https://www.patreon.com/scishow -------