An 8 pound chunk (almost 4,000 grams, as these specimens are often described) of what I believe to be obsidian, (a volcanic glass), measuring 8" by 6 1/2" by 5". It is challenging to photograph, but what looks at first much like a generally black object actually has beautiful, emerald-green crystalline-appearing inclusions. The way it has cleaved and is so glass-like is typical of obsidian. It could stand to be polished up, as it has an abraded surface and edge wear in places from handling. Once polished, it will be a conversation-starting paperweight for your office or just an interesting décor item, in the manner of corals, fossils and other natural history specimens currently installed in interior settings.
Natural history decor 8 pound specimen of green obsidian volcanic glass