Just to add a little more information.
Zinc that isn't galvanized usually has a yellowish/goldish color. But galvanized does have the chalky gray mentioned above.
Also, austenitic stainless steel (aka 300 series) has nickel in it's chemical composition. Out helps with high temps and oxidation resistance.
The cheaper, magnetic, ferritic stainless steel (400 series) didn't have nickel... Or very little. Also it will rust especially after exposed to high heat regularly. This is why stainless steel used in cheaper grills still rusts out.
If I've started anything incorrectly feel free to correct me.
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