I think so.
yes they can. especially if they are “simple” styles. yellow gold and white gold don’t go well together unless one of the pieces is two-colored gold.
Nope. Pearls with pearls and diamonds with diamonds. Always.
The only exception is when you have a piece of jewelry that contains both - then you can accessorize with either.
yes, but i think pearl necklace and diamond earrings are better.
Probably not, if your diamond solitaire necklace is pure diamond and your pearl stud earrings have no hints of diamonds on it at all.
Wearing both together would make one outshine the other- or at worst, just makes it look like you’re trying too hard to outdo someone else at the function. Not a good idea.
When wearing diamonds, you’ll generally look very sparkly because of it’s reflective elements- it’s more of like going for the ’screaming sophistication’ look- while wearing pearls on the other hand, you’re going for the more understated sophisticated look, more of ‘woah. classy!’ thing.
Hope this helps.