Here's why:

* Rhodium is a hard, silvery-white metal that is highly resistant to corrosion and tarnishing. It's often used as a plating for white gold and platinum jewelry to give it a brighter, more lustrous finish.

* Sodium is a soft, highly reactive alkali metal. It is extremely dangerous to handle in its pure form and would not be suitable for jewelry making.

Let me know if you have other jewelry-related questions!