When looking for gold in california, which of the following characteristics below would be the best way to distinguish gold from pyrite?

Some ways to tell the difference between gold and pyrite would be the shape, color, as well as weight. Weight is a major characteristic because gold is one of the heaviest naturally occurring metals known to man, so if you were to find a large nugget of gold it would be noticeably heavier than a similar sized nugget of pyrite. Shape is also a defining characteristic of pyrite because as it is forming, it takes on the shape of crystals. This is something gold does not do, as when it is forming it takes shape of non symmetrical flakes and nuggets. Color is also a significant characteristic because to the trained eye you can easily spot the difference between pyrite and gold. Pyrite has a dark yellow color similar to brass, whereas gold has a vibrant, reflective yellow color that is easily identifiable. I hope this helps :)

The best ways is to know that the Pyrite is known to be the fool's gold and its has been tricked countless prospects into thinking they've found real valuable gold when they really didn't.   

Organisms are more likely to be more preserved in mud than sand because mud is moist and wet, while sand is very dry.