Amgueddfa Blog: Daereg

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.

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/




 

Dangosodd ddarganfyddiad y deinosor Cymreig, Dracoraptor, bod deinosoriaid yn byw yn ne Cymru 200 miliwn o flynyddoedd yn ôl. Petaech chi'n teithio 'nôl i'r cyfnod hwnnw, fe fyddech chi hefyd wedi gweld ambell i famal bychan, tebyg i lygoden goch, yn cuddio yn y tyfiant. Rhain yw rhai o'r mamaliaid cynharaf yn y byd.

 

Gellir darganfod esgyrn a dannedd y creaduriaid bach blewog yma mewn ogofau a mewn craciau mewn cerrig - efallai am fod rhain yn cynnig lloches, neu le i aeafgysgu. Darganfyddwyd y ffosilau cyntaf ohonynt mewn chwarel yn ne Cymru rhyw saith deg mlynedd yn ôl. Mae Palaeontologwyr wedi bod yn dadansoddi'r ffosilau, er mwyn creu darlun fwy cyflawn o sut greaduriaid oedden nhw. Enw un o'r mamaliaid cynnar yma yw 'Morganucodon', sy'n golygu 'Dant Morgannwg'.

 

Mewn prosiect ymchwil newydd wedi'i gefnogi gan Y Cyngor Ymchwil Amgylcheddol, defnyddiodd wyddonwyr o Brifysgol Bryste belydr-X pwerus i sganio'r esgyrn bychain, i greu darlun digidol o'r creaduriaid. Cymharwyd y darluniau digidol yma gyda mamaliaid modern, er mwyn ail-greu strwythr cyhyrau'r anifail. Ychwanegwyd rheiny i'r darlun digidol. Wedi hynny, defnyddiwyd rhaglen arbennig i asesu sut y byddai'r esgyrn a'r cyhyrau'n symud. Astudiwyd dannedd y creaduriaid mewn manylder - roedd rhai mamamliaid cynnar yn meddu ar ddannedd ddigon cryf i grensio pryfaid gyda casys adennydd, ac eraill ond yn medru bwyta pryfaid meddal.

 

Mae model hyfryd o Morganucodon, wedi'i greu can Bob Nicholls, y palaeoartist, i'w ganfod yn ein orielau hanes natur yn Amgueddfa Genedlaethol Caerdydd. Mae'n edrych fel creadur bywiog iawn a'i enw yw 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.

 

Beth sydd ar droed yng nghanol Dinas Caerdydd?

Pwy (neu beth?!) sydd wedi difrodi cerflun Thomas H Thomas ac achosi anhrefn ar hyd strydoedd Caerdydd?! 

Os oes gennych unrhyw wybodaeth neu luniau all ein helpu, rhannwch nhw gyda ni drwy drydar a defnyddio #DeinoYnDianc cyn i’r sefyllfa droi’n fwy brwnt bythtag.

Mae’r stori’n newid o hyd a byddwn ni’n rhannu’r newyddion diweddaraf â chi yma.