crystal gems on exterior - legal?!

Hi everyone; so basically I’m obsessed with crystals and sparkly stuff, and I have a lot of my interior covered in them. I know it’s not to everyone’s taste, so please don’t hate 😆 but now I wanna add some to the exterior of my car, but think it’s best to check first with the rules on this before I go ahead. Can’t find any info anywhere about this, but need to know if it’s even road legal to drive a car with sparkly crystal gems on the exterior. Any help would be appreciated. Thanks 🙏