Quartz crystal is used to keep time and actually it is a lot more accurate than mechanical wind up watches.
Here is what my book says
type: mineral
Color: pale to dark pink, milky or glassy-looking
Found in: Brazil, France, USA
Rose quartz is a member of the quartz family, one of the most common crystals on Earth. You can find traces of quartz hidden inside many rocks. Quartz releases electricity in a very predictable way when it is squeezed, making it great for helping you keep time- quartz is used in many watches. With its pretty pink color, rose quartz is popular in jewellery
Note: this write up doesn't say that it took millions of years to form also lol. You'd think for a crystal that kept time, maybe it could just tell us how old it is? lol. I think it just means it has a regular pulse or beat.