California Code
ARTICLE 2 - The Platinum Group
Section 22120.

22120. The provisions of this article shall apply exclusively to the following metals and to the alloys of each:

(a) Platinum

(b) Iridium

(c) Palladium

(d) Ruthenium

(e) Rhodium

(f) Osmium.

(Added by Stats. 1941, Ch. 316.)