In short, rhodium in the form that is on your jewelry is not toxic!
I have researched this topic fairly extensively. Initially like probably most of the posters, I did a simple google search and found a bunch of places saying that it was toxic, but no one really said how it was toxic (through skin contact, from ingestion, etc…). So I looked a bit deeper. I then found this article:
This article talks about how rhodium plating should be banned, why? Because of the process of plating the rhodium is dangerous, not because a group of people after wearing rhoduim plated rings got cancer. Then I looked even deeper and found the following scientific article:
Toxicity of Industrial Metals by Ethel Browning M.D.
In this article, rhodium is discussed in both the dust and solid metal form. In short, it’s determined that the dust form of rhodium is hazerdous. There was also tests done with the effects of wearing different types of metal rings (platnium, palladium, and rhodium). Out of the 3, rhodium caused virtually no reaction from the skin.
No toxic effects of rhodium have been reported from animal experiments or <br />from observations on human beings. Its harmlessness as a skin irritant was <br />indicated in a case of contact dermatitis. Sheard (1955) observed that a wor- <br />ker wearing rings coated with rhodium (see p. 240) showed negative rhodium <br />patch tests, though all the other metals of which the rings were constituted <br />gave positive results.”
I also referenced the Toxicology Data Network:
This study shows that rhodium DUST is toxic (through inhalation and ingestion) but besides that, it’s not toxic.
I really wanted to look into this as I really did not like the idea of potentially wearing a piece of jewelry every day of my life that could be toxic to me. It’s unfortunate that in making the rhodium plating that the conditions are hazardous, but for the wearer of the rhodium plated ring, its perfectly safe.