Because <span>Gold is a very inert metal, and won't really react with oxygen in the air.
The only reason other metals tarnish, such as copper, silver, steel/iron, is
because they're freely reacting with air, to produce a metal oxide surface layer. </span>
The insulating ability of a substance is a physical characteristic and not a chemical one. A physical property is a characteristic that distinguishes one type of matter from the other and can be observed without changing the identity of the substance. A chemical property describes how one substance changes into another in a chemical reaction.
