I don't know what color the polyps the jewelry I bought were, but I was reading till 2 am last night about black coral and yes you're right about it being a type of gorgonian. they come in all differnet colors depending on depth and genus. I believe there are 5 or so different types of black coral. Yes they grow in deeper waters but I saw something on youtube about hawaii has some shallow water black coral that they use for jewelry. I want some live black coral to match my necklace. I want the kind that has thorns on it.