HomeArticlesDiamonds, Pearls and Atomic Bomb Stones – Periodic Table of Videos
Diamonds, Pearls and Atomic Bomb Stones – Periodic Table of Videos
October 11, 2019
So now I’m going to show you Raman’s collection of minerals Lots of people had collections of minerals but his is special because he collected them all personally And so … brought them back here So there is his own character, if you like, in his choice of things that he collected Let’s go and see some of them There’s a bewildering number of things to see And one of the first things which is really very special is over here When Raman first moved into this institute, there was no electricity So he had this special device to reflect the Sun off this mirror into the room As you know the Sun moves around as the time of day But there’s a special clock here and a system of levers so that as the Sun moves, the mirror moves to keep the sun shining into the room So let’s go look at some of the samples I’ll just show you a few … whichever ones look really interesting So he looks really wise These are interesting pearls which come from oysters as you know Raman was very interested in the scattering of light And the silvery color of pearls is due to the scattering of light between the layers of calcium carbonate that’s laid down in the pearl Here there are all sorts of gemstones …and, Jade from China, samples from Brazil He traveled all over the world Quartz, silicon dioxide (SiO2), which contains inside it some liquid that was trapped during the geological process Using light, which can shine through this he could find out what the liquid was without damaging the crystal and he showed that the liquid was water with a mixture of carbon dioxide and methane So, if you think about it it’s really quite clever Without damaging the crystal, you can find out what’s inside There’s a really nice story about this piece of quartz He got it from a farmer who brought it to sell it to him And he bought it and then discovered about the liquid afterwards Otherwise, the farmer would’ve probably ask for a lot more money Here there are opals Again the color is due to the scattering of light… …something that fascinated Raman Over here, there are some things which are very interesting but actually rather ordinary stuff So up here are these really nice crystals And they’re sugar! Normally we see tiny crystals of sugar I’ve never seen such big crystals of sugar in my life I’ve got quite small hands but they’re still quite big And even bigger down here are two salt crystals These are natural salt crystals that Raman collected from a salt mine in Poland And up here there are rather nice crystals of copper sulfate Over here we have some nice samples of sulfur I’ve got a small sample at home but it doesn’t look anything as beautiful as this And presumably this came from somewhere volcanic And these samples here have a specially interesting story These are artificial crystals Apparently, there was a power cut – the electricity went off for several days And not far from here there is a steelworks or, there was, where they made steel continuously in very hot furnaces But when the electricity stopped, Raman realized that the furnaces would stop and there might be good crystals there So he rushed off and before they could start up the furnaces again he got these really nice crystals of carborundum So now I want to show you the thing that I find the most moving in the whole of this display Over here are two stones that come from the center of Hiroshima, the city that was attacked with the first-ever atom bomb And these are pieces of mineral that have melted The melting point is about 1800 degrees centigrade And they apparently melted in the center of Hiroshima Raman was given these pieces of stone by the city of Hiroshima in recognition of his active opposition of the use of nuclear weapons But he was quite careful and he said send them to me and he had them tested for radioactivity before he added them to his collection In here, we have series of samples of rock that don’t look particularly special but above them are some UV lamps and if we switch out the light with the visible light then suddenly, you see something really quite interesting that all these minerals begin to glow And they glow because they are absorbing UV light and then some of the energy is lost inside the crystal structure and they emit visible light In here’s some Ruby and the large lump in the middle is artificial synthetic Ruby and the little bits round about are natural Ruby and you can see that the natural Ruby fluoresces very nicely whereas the artificial stuff doesn’t This sample here is interesting … something I’ve never seen This rather grey mineral is called crocidolite and it is what asbestos is made from You’ve probably heard that asbestos fibers – these very fine fibers – that were used for insulation can be breathed in and cause cancer This sample is what asbestos is made from And because it’s dangerous, I’m not going to pick it up Just as we were going, Shashi, who is the curator of this museum, produced another treasure for us These are natural diamonds for optical windows which give you very strong windows that you can use for high pressure vessels and so on And look at the size … it’s amazing! I’ve seen diamond windows before but never seen natural ones of this size These are natural diamonds which have been chopped to give you a slice of this So the actual diamond itself must have been very much bigger and diamonds of that size are extremely valuable [Raman’s Nobel Prize] So this is the citation and here, as you can perhaps guess, is the medal [Raman’s Spectroscope] Whenever he saw something interesting – a flower, a rock, whatever, he could look through this and see the spectrum [Objectivity] Hello everyone! Welcome back to objectivity! [Objectivity] Of course I’m wearing gloves [Objectivity] But you know we mean business today because Keith is wearing gloves! [Objectivity] Wow!