Amgueddfa Blog: Geology

Lava medallions and coins in lava from Mount Vesuvius, Italy

The National Museum Wales Petrology (Rock) collection comprises 35,000 specimens, with many interesting rock samples from across Wales and the wider World. In the drawers of the Italian collection, alongside the pumice, volcanic ash and obsidian are these curious rocks.

NMW GR.206 - Lava medallion with stamp of unknown figurehead, Vesuvius, 1871. (front)

They are called lava medallions or tablets, and along with coins embedded in lava they were probably first produced in the mid-18th Century when the ‘Grand Tour’ become fasionable among the wealthy elite of Europe.  Taking in European cities like Paris, Rome, Venice, Florence and Naples, the ‘students’ would travel with a tutor on a Grand Tour to learn about languages, geography, culture, art and architecture. When passing through Naples, the volcano of Mount Vesuvius (Vesuvio) became a must see stop on the tour. Forget postcards, fridge magnets and selfies, the take home souvenir of the day was the lava medallion!

People have long been fascinated by destructive power of Mount Vesuvius, the volcano had lain dormant for centuries before the famous eruption in 79 A.D. when the Roman cities of Pompeii and Herculaneum were destroyed. Over the last two thousand years, the volcano has erupted many times. Between eruptions, Vesuvius can lie almost dormant for long periods of time before erupting violently once again. Volcanoes the world over that erupt in this explosive style after long periods of dormancy are known as Vesuvian eruption volcanoes.

To make a lava medallion, molten lava would have been retrieved (by some very brave individual with a long stick!) from a recent lava flow or lava close enough to the surface that was accessible and still hot enough to be malleable. It was then moulded, pressed with a stamp, or embedded with a coin, cooled in a bucket of water and sold to a passing grand tourist.

The French Revolution in 1789 marked then end of Grand Tours as they were known, but with the advent of the railways in the early 19th Century and the beginnings of mass tourism, these distinct souvenirs once again became popular take-home keepsakes, and they were produced in their thousands.

Over the years many of these medallions and lava coins have found their way into museum collections across the world. They often depict kings, Roman Emperors, famous scientists or events. All of the medallions and coins in the AC NMW collection date from the 19th Century, and originate from Mount Vesuvius, but examples in other collections have originated from Mount Etna, Sicily.

If you would like to know more about lava medallions, please contact Andrew Haycock via:

https://museum.wales/staff/665/Andrew-Haycock/


NMW GR.206 – Lava medallion with stamp detailing date and place of collection, Vesuvius, 1871. (back)

NMW 15.133.GR.1 - Vesuvius, 1834. ‘note with specimen 'medallion struck in lava when it was in a hot and pasty condition’ (front)

NMW 15.133.GR.1 - Vesuvius, 1834. Note with specimen 'medallion struck in lava when it was in a hot and pasty condition’.

NMW 15.277.GR.6 – Lava with embedded coin (Victor Emmanuel II), Vesuvius. (1860s?)

NMW 15.277.GR.3 – Stamped tablet with [S]ALVATOR MADONNA one side and 1844 on other. (front)

NMW 15.277.GR.3 – Stamped tablet with [S]ALVATOR MADONNA one side and 1844 on other. (back)

NMW 24.113.GR.6 – Lava with image of Galileo, Vesuvius, 1879. (front)

NMW 24.113.GR.6 – Lava with image of Galileo, Vesuvius, 1879. (back)

NMW 15.133.GR3 – Lava with embedded coin (corroded), Vesuvius.



 

 

The discovery of the Welsh dinosaur Dracoraptor showed us that dinosaurs lived in the Jurassic of south Wales 200 million years ago. However if you went back to that time you would also have seen little shrew-like mammals hiding in the undergrowth, these are the very earliest mammals.

 

The bones and teeth of these tiny, furry creatures are preserved in caves and fissures in rocks, where perhaps they were sheltering, or even hibernating during cold winters. Fossils of these minute mammals were first found in a quarry in south Wales seventy years ago. Palaeontologists have pieced together the fragile bones to reconstruct what the animals would have looked like. One early mammal has been named Morganucodon which means "Glamorgan tooth”

 

New research undertaken at Bristol University, funded by the Natural Environmental Research Council, used powerful X-rays to scan these tiny bones making it possible to piece together the fragments digitally. Then, using modern mammals as a guide, palaeontologists digitally recreated muscles on scanned images of the skeleton. Bristol scientists used computer simulations to work out how a skeleton worked. By looking at their teeth they could tell that some early mammals were able to crunch insects with hard wing cases, while others could only bite softer ones.

 

We have a new display in our Insight gallery highlighting this research which includes an amazing model of Morganucodon, made by palaeoartist Bob Nicholls. It looks unbelievably lifelike and answers to the name Morgie!

There are numerous hash tags celebrating the natural world on Twitter. However, #FossilFriday remains one of our favourites. Each week we showcase the wonderful paleontological collections that are housed at National Museum Cardiff as well as the research that goes on every day behind the scenes.

We not read some of our latest #FossilFriday Tweets and discover more about the fascinating world of fossils

 The numbers of specimens in geological collections in the UK alone reach into the tens of millions. These collections are important for research, education and also commercially. Museums hold collections, but so do individuals and companies; exploration companies keep rock core samples which can be as valuable as £1,000 per meter.

There is now sufficient evidence to dispel the myth that geological collections are inherently stable and require fewer resources to preserve them than other areas of museum collections. In fact, a proportion of geological collections demand a level of attention and maintenance comparable with archaeological metal collections. This includes similar environmental and pollution-related considerations.

About 10% of known mineral species are sensitive to changes in temperature or humidity, or may react with air pollutants. One such mineral is pyrite – common in geological collections and one that is particularly troublesome. However, despite centuries of research on pyrite decay there is a dearth of knowledge in subjects that would help museums improve the effectiveness of their care of geological collections. This includes the categorisation of damage to specimens, methodologies for objective routine condition assessment, the definition of an adequate storage environment, and successful conservation treatments.

Currently available methodologies are not suitable for routine collection monitoring, results are not necessarily replicable, and, in the absence of guidance on suitable storage conditions, triggers and the suitability of conservation actions are difficult to determine. We need a more robust approach to the delivery of preventive conservation of geological collections.

We have now teamed up with the EPSRC Centre for Doctoral Training in Science and Engineering in Arts, Heritage and Archaeology (SEAHA) at University College London, University of Oxford and University of Brighton to investigate these aspects of preservation of geological collections. A four-year studentship has been advertised which will be based at Oxford University but spend a considerable amount of time working at National Museum Cardiff. If you are interested in this subject, and have a background in, ideally, geology, chemistry or engineering, please do get in touch.

Find out more about Care of Collections at Amgueddfa Cymru - National Museum Wales here and follow us on Twitter.

 

What's all this dinosaur havoc going on around Cardiff City Centre?

Who (or what?!) damaged our newly erected statue of Thomas H Thomas and is causing mayhem on the streets of Cardiff?!

If you spot any monstrous goings-on or dino-mischief around Cardiff then please let us know over on Twitter using the hashtag #DinoOnTheLoose.

This is an unfolding story - updates will be brought to you as we become aware of them.

Follow the story: #DinoOnTheLoose