I have a little trick I use to get a better pic of an item. Put it on a white background and don't use a flash. If you can use indirect lighting. And it should come out. Just an FYI that might help.
The stone, (only one) i do believe is a nice "JADE" this necklace is a piece of costume jewelry, gold tone,,, I THINK,,,,,the only marking on it is "PERI" the chain is for sure just gold-tone as i had to add it, it did not have a chain with it. this is the best picture i can get with my little camera, sorry,,,:-)