File:Pumice (24-25 August 79 A.D. eruption of Mt. Vesuvius, east of Naples, Campania, Italy) 3.jpg

English: Pumice from the Holocene of Italy. (American 1 cent coin for scale)

Mt. Vesuvius is the most famous volcano in Europe and has erupted on a semi-regular basis over the last 2000 years. Vesuvius is a ~300,000 year old subduction zone stratovolcano located just east of the major Italian city of Naples. On 24-25 August 79 A.D., a large explosive ash eruption destroyed and buried five Roman towns (Pompeii, Herculaneum, Stabiae, Oplontis, and Boscoreale). A written, eyewitness account of the eruption still exists. Pompeii has been excavated by archaeologists since its discovery in the mid-1700s. It is widely considered to be the most significant archaeological site on Earth. Pompeii is rarely mentioned in ancient historical records, but historians and archaeologists understand Pompeii better than Rome itself in many ways. The most famous Pompeii discoveries are casts of people (and animals) preserved in the volcanic deposits. The casts are empty spaces in the ash and pumice, subsequently filled with plaster and the matrix removed.

The pumice samples seen here are from the late August 79 A.D. eruption that buried Pompeii. This eruption produced ash and pumice having phonolite and tephriphonolite compositions - both are alkaline, intermediate, extrusive igneous rocks. The phonolite pumice is reported to be whitish in color and the tephriphonolite pumice is supposedly gray. The natural colors of these samples are between white and gray, so I'm not sure whether they are phonolite or tephriphonolite.

Locality: ruins of the Roman city of Pompeii, east of Naples, east-central Naples Province, coastal Campania, southern Italy