Chemical Formula: SiO2 Moh's Hardness Scale: 7 Quartz: You know it, you love it. It’s the second most common mineral in the world, and it comes in just about every color you can think of. Some of the more colorful varieties, like amethyst and citrine, are used as semi precious gemstones, but quartz is more than just eye candy. We use it to make glass, as an additive in concrete, and it’s even in our watches and electronics.But to geologists, quartz is so much more than that. See, when quartz is hit with intense pressure or temperatures, it can cause the internal structure of the crystal to change into something called shocked quartz. So finding shocked quartz can tell us about events in the past, like meteor strikes, and we can even calculate how powerful they were, just based on that quartz. Not bad for such a common mineral!
