Did you know that it rains diamonds on Saturn and Jupiter?
This happens because lightning storms on these planets turn methane (A common element found it both planet’s atmospheres) into carbon, and when it falls, hardens into chunks of graphite. The closer the graphite gets to the ground, the more pressure is applied to the point that the graphite gets so compressed, that it turns into a diamond. The biggest of these diamonds being a centimeter in diameter. That’s big enough to put on a ring! Well, uncut of course.