After all the problems recently in Pompeii, with houses collapsing, I'm sorry to report that two early Ptolemaic obsidian cups were destroyed at the National Archaeological Museum in Naples in an accident. The exact reason why they 'fell' is unclear, but they are now smashed to smithereens ... They were excavated at the villa San Marco di Castellammare (Stabiae) in 1954, and the full museum record is here. The skythos is shown in the first photograph.
What makes these cups interesting is that they were made in Egypt in the wake of Alexander the Great's conquest, then later collection by a noble Roman family whose villa complex was buried by Vesuvius in AD 79. Egyptian antiquities were also collected by Herodes Atticus, and found at his villa at Loukou in the Peloponnese. Although most of the Egyptian antiquities in Naples Museum were collected in the 19th century, a number were found in Roman contexts, and others seem to have come to Italy even earlier, to the Greek colonies. Another interesting imported item in Naples is an Indian ivory statuette of Lakshmi found in a house in Pompeii (JSTOR) - collecting is nothing new, nor is an active import-export trade.
Obsidian is formed when lava from a volcano meets saline water, but the irony is that Vesuvius' flow had preserved the cups, and modern Italian museum technology has destroyed them. Staff initially tried to cover up the incident last Sunday, but visitor rumours meant that the news finally had to be confirmed.
Napoli, crollano mensole al Museo Nazionale in frantumi due coppe di ossidiana di epoca tolemaica: danni incalcolabili - Il Mattino