Stainless steel bead cap findings from Rings & Things are not plated -- they are simply sleekly polished Stainless Steel. 304 stainless steel is the most popular grade of stainless steel. It is 18-20% chromium, 8-10.5% nickel, 0.08% carbon, plus iron and trace elements. It is commonly used in the food industry (sinks, coffee urns, beer/brewing, citrus and fruit juice handling, etc). The chromium creates a very thin chromium-oxide layer on the surface of the metal which prevents it from rusting. The advantage of stainless steels over plated steels is that, if scratched or damaged, the stainless steel 'self-repairs' as a new chromium-oxide layer is formed. In plated steels, scratches in the plating can lead to corrosion of the steel underneath.
The same corrosion and stain resistance that make 304 stainless steel great for food handling, also make it popular for jewelry.