What is the chemical symbol for gold?

Au, from the Latin aurum, shining dawn. Several symbols come from Latin rather than English for the same reason - Fe for iron from ferrum, Pb for lead from plumbum, Na for sodium from natrium, W for tungsten from wolfram. These are the metals known since antiquity, named long before English existed.

Gold's chemistry is its whole history. It barely reacts with anything, so it does not tarnish, corrode or dissolve in ordinary acids, which is why gold recovered from a shipwreck comes up bright. That inertness is why it became money: it survives, it can be melted and divided without loss, and it is rare enough to be worth carrying. It is also why its colour is unusual - most metals are silvery, and gold is yellow because relativistic effects on its fast-moving inner electrons shift its absorption into the blue.

Almost all of it is older than the Earth. Elements this heavy are not made in ordinary stars; the current best account is that most gold comes from neutron star collisions, one of which was observed directly in 2017 and produced a measurable signature of heavy elements. The ring on somebody's finger was made in a collision between the densest objects in the universe and has been sitting in this planet's crust since it formed.