What does "angry diamond" mean?

This is not an idiom.

This is created by the author and you should try to imagine what it may mean

So, what's

Fitzgerald seems to create many phrases that are not standard expressions -- we can only guess what he meant by them. "Angry diamond" has probably never been uttered or written anywhere else. Perhaps he meant that the woman was beautiful, though angry.

When I first read your question, I thought perhaps it was supposed to be "an angry diamondback," since it is followed by the word "hiss

I'm sorry that you feel that - it is still one of the great romantic novels. Perhaps it is best suited to the adolescent.

I had to read it in 10th grade. I greatly preferred it to anything every written by Thomas Hardy.

I don't remember the odd use of language, though.

As well as the implications of "beauty", "hardness", and "expensiveness", diamonds are sometimes regarded as "cold". Then too, an angry person often has "flashing eyes", in fiction; and diamonds are noted for their "fire".

MrP

after seeing some of your questions I will probably never read it -- I find his use of language somewhat annoying.

Whew! That was cold water!

Well, if I have offended the ghost of F. Scott Fitzgerald, I apologize. It's just not my cup of tea. [C] He's not the only acclaimed author I don't care for -- recently in the car my husband was listening to an audiobook of Orlando by Virginia Woolf. When he turned off the tape I asked if he was listening to it because he had lost a bet.

In any case maybe we should stop arguing in front of the children.

CJ

Even if someone doesn't like the language in Gatsby, I feel there's a great drama which is left to enjoy.

Sorry -- I didn't mean to be so controversial! In the future I'll try to stick to language questions and avoid expressing gratuitions opinions.