Claire, a bangle in that color would be gorgeous.
Crytsalline, I found this on black jade.
Black Jadeite - There are in fact two types of so-called black jadeite. One of these comes from Burma, and is really gray rather than black, and the other comes from Guatemala, and is truly black.In the case of Guatemalan black jade, it was used in Prehispanic times to make celts and other artifacts. The Aegirine-augite (chloromelanite)-rich rocks, or black jade, are metamorphic rocks with a fine-grained-to-cryptocrystalline texture. The color is given by the pyroxene aegirine-augite (chloromelanite) and by taramite, a sodic-calciic amphibole. The amphibole is markedly pleochroic in blue, brown, and violet. This rock also contains titanite, albite, analcite, grossular, and white mica.Black jade in Mesoamerica resembles basalt and is very durable. It takes a very good polish and shows little grain definition.