These crystal stars made from pipe cleaners and a simple borax solution are SO COOL. And they're really easy to make! Leave them overnight and crystals magically form! Borax Crystal Star Ornaments OK you guys, I think I've fallen in love with another kids activity. These borax ornaments are so easy to make, and they look SO COOL when they're done! It takes a few hours to grow the crystals, but the actual work involved with putting them together is really fast. We whipped up our crystal stars in about half an hour before we left to visit my inlaws