Hand blown glass pretty durable set with jet spacers and four pieces of carved black bone.Jet is a soft, opaque black gemstone, easily identified because it is very, very lightweight. Jet is composed of carbonized wood. The material was first found near the River Gages and mentioned by Pliny in Ancient Greece. Jet is rather difficult to find today, but there is quite a lot in China. Jet has been used since the Bronze Age as an ornamental stone.Had been $120