The Science and Beauty of Crystals
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ChemistryNobeliumHuman subject researchSoapAnesthetic
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CrystalNobeliumStratotypGemstoneChemical formulaHardnessCancerAluminiumGemstoneChromiumShear strengthChemical formulaLecture/ConferenceMeeting/InterviewComputer animation
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HardnessWine tasting descriptorsLecture/Conference
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NobeliumCancerStratotypCrystalGemstoneChemical formulaHardnessPedosphäreCrystallographyOrigin of replicationPhysical chemistryChemistryLebensmittelfarbstoffCell (biology)PigmentSea levelSetzen <Verfahrenstechnik>Aluminium oxideChromiumTitaniumIronSapphireBlue cheeseEmeraldChemical elementTrace elementAluminiumBerylliumPhotoreceptor cellOrigin of replicationSapphireChemical elementColourantSea levelPedosphäreSetzen <Verfahrenstechnik>GemstoneChromiumLactitolAbundance of the chemical elementsPhysical chemistryChemical formulaWursthülleCrystallographyAluminiumEmeraldPigmentBlue cheeseFunctional groupChemistryLegierenTitaniumAddition reactionCell (biology)Chemical propertyThermisches KrackenAluminium oxideColumbia RecordsBiodieselFireGoldActive siteOctane ratingCancerBranntweinWine tasting descriptorsBase (chemistry)SeleniteStratotypLamb and mutton
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PolyesterCapillary electrophoresisTube (container)QuartzSyrupFreezingHuman body temperatureChemistryPhysical chemistrySurface scienceWaterGrowth mediumChemical vapor depositionProcess (computing)MethaneMixtureHydrogenSurface scienceQuartzElectronic cigaretteWaterFreezingPolywasserGrowth mediumGlassesViscosityOceanThermoformingChemical vapor depositionStatic mixerConcentrateChemical propertyMethanisierungSilicon dioxideHuman body temperatureHydrogenDrop (liquid)Separation processNeotenyAzo couplingAbzug <Chemisches Labor>Psychological traumaAreaTube (container)Physical chemistryFiningsChemistryChemical reactionProcess (computing)PharmacyAgeingGesundheitsstörungComputer animation
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NobeliumChemical vapor depositionProcess (computing)HydrogenMixtureChemical reactionMethaneSubstrat <Chemie>PolyesterProcess (computing)PharmacyGemstoneStructural steelPoultryTool steelSteelMaterials scienceCarbon (fiber)Synthetic oilAluminiumSapphireElectronic cigaretteButcherFrictionLecture/ConferenceMeeting/InterviewComputer animation
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NobeliumComputer animation
Transcript: English(auto-generated)
00:15
Last year, I started a series of lectures here in Lindau
00:21
titled Science and Aesthetics. And the subject last year was the science and beauty of soap bubbles. This year, the subject is the science and beauty of crystals. So, let us start.
00:41
Archaeological discoveries of jewelry from ancient civilization revealed the old admiration of crystals' beauty. People used crystals to decorate jewelry, and they had marvelous pieces of jewelry. Here are a couple of examples, which I will show you shortly. Along with the artisanship of crystal-decorated articles
01:03
came the belief that crystals have powers that affect people. And, regretfully, such beliefs are very much alive in our time. For instance, if you go to the Internet and seek information on a crystal, let's say a ruby, then you get something like this.
01:23
You get a picture of a ruby and some details about the ruby. And here they are. This is from the Internet. So, it says the following. Pronunciation, ruby. That's a fact. Formula, aluminum oxide, and a little bit of chromium. That's a fact.
01:44
Stone qualities, aha. Courage, passion, strength, adventure. That is not a fact. Hardness, MOS 9. This is science. Chakras, aha. Do you know what chakras is?
02:04
The Indian guys here know what chakras is. It's how, what part of the body the crystals affect you. And this particular one, ruby, affects you in the root, which means your feet. Remember that.
02:20
That's not a fact. Zodiac, zodiac. Leos, Scorpio, Cancer, and Sagittarius. That's not a fact. Locality, these are facts. Sri Lanka, Burma, which is Myanmar, Thailand, India, Brazil, and the USA. This is what people know about crystals.
02:43
And in fact, at one time, many years ago, I gave a talk in Israel on structure of crystals, purely scientific in university, and there was a journalist at the crowd. And after I finished my talk, he came to me and he was very mad. He said, you are very disappointing.
03:02
I said, why? Because you didn't talk about the effect of crystals on people. And I said, oh, you mean blood diamonds and how mining crystals affect the hard workers? He said, no, no, no. How do crystals affect different parts of your body?
03:22
He chased me to the car. I couldn't get rid of him. Okay, so the current idea about the structure of crystals had to wait until the dawn of the logical and scientific times. Johannes Kepler, remember the name, of course,
03:41
proposed the pecking of spheres geometry in 1611 and started the science of crystallography. However, the experimentalist has to wait, until von Laue gave us X-ray diffraction in 2012, remember, Randgen found X-rays in 1895,
04:04
17 years later came von Laue with X-ray diffraction, and shortly thereafter, the Bragg, father and son, came with the Bragg equation, and from there on, we have science in crystallography. Understanding physical and chemical properties of crystals
04:22
came with a vast number of study that followed. My talk will focus on explaining scientific origin of our fascinating with crystal, and I will talk only about a very small type, small number of crystals which are transparent.
04:42
I will describe it. So, let's look at ancient jewelry pieces. Here is one. I'm sure that many of you would like to have such a piece. This is made of gold, and it's very nicely decorated, and today you can see in rare cases such a beautiful piece,
05:02
and this is ancient Greek. Here's another one, also gold and very nicely decorated, very nice pieces of jewelry, and the stones play an important role here. So, first of all, when we talk about colors of crystals,
05:20
how do we see colors? How do our eyes work? The retina, the retina is the back part of the eyeball, in the back of the eye, and it looks like that. Light comes from here, so this is front,
05:41
and it hits the retina, this is the thickness of the retina, and this is the back of the eye, right here. And you have two types of cells there. You have rod cells, which are these, and you have, like so, and you have cone cells,
06:00
and the function of these is totally different, as I will explain. Rods and cones. Rods and cones react differently to light. The rods, let's go back for a second. The rods, there are many of them. The rods are very sensitive to light,
06:22
and can be triggered by a single photon, extremely sensitive. The color perceived is gray. You don't see colors with the rods. In a very dim level, we see only by the rods, and therefore we do not see colors at very low light levels.
06:41
The cones are made of three pigment types. There are three types of cones, red, green, and blue, and thus the color seen is the percentage of red, green, and blue. Okay, so the human eye is more sensitive to green light. I hope you know that.
07:01
This is why when you use a laser pointer, try to use a green laser rather than the red laser, to which the eye is not very sensitive. We will now discuss the formation of color in seven transparent gem quality crystals, and these are transparent crystal only. And let's start with the color of sapphire.
07:21
Single crystal of alumina, aluminum oxide, or sapphire, is transparent and colorless. And these are produced in abundance as windows for different purposes. It is hard, sapphire is very hard, and therefore it is useful in many applications.
07:42
It is also very transparent and very clean. If you add some chromium to it, it becomes red, and it looks like that. And people call it ruby, which is a gem. If you add some titanium and iron, minority elements,
08:03
then you get this, and people call it blue sapphire. And it's all the same. Sapphire can have many colors. These are not the only two colors you can have, and here is an example of many sapphires with many colors,
08:21
and it depends on the minor additives to the basic structure of alumina. Let's say a word about emerald. I love emeralds. I think they are the nicest gems. So here it is, this is a natural crystal of emerald,
08:41
and people make jewelry, and here is a wonderful piece of jewelry. Emerald, the chemical composition is beryllium, aluminum, silicide, as in the formula you can see it is here. And the trace elements are chromium, vanadium, iron, manganese, etc. And then it depends on the quality. By the way, emeralds, this is out of my lecture,
09:03
but they all have cracks in them, and so people fix them by introducing some oil into the cracks, and then the color looks very nice. Emeralds drive their beautiful green color from the presence of chromium and vanadium.
09:23
And last but not least, diamonds. Diamonds are, as you know, made of carbon, and here are some beautiful diamonds. I take this one. You can take whatever you want. And diamonds are amazing, and I'll tell you the story of diamonds shortly.
09:43
So why do gemstones look colored? Well, some processes, including electron transition between orbitals, the electron can jump between orbitals, that require energy, and the energy, in some cases, can come from visible light.
10:02
So some processes, including electron transition between orbitals, absorb specific wavelengths from the visible spectrum and let other colors pass. So some from the visible spectrum, let's say sunlight, some colors are absorbed and let other colors pass.
10:21
And what you see are the colors that are not absorbed. Blue sapphire is blue because this is the only color not absorbed in the crystal. If you look at blue sapphire using candlelight, try to do that if you have sapphires, it will look black. It looks black because the candlelight is rich in red wavelengths
10:41
and very poor in blue. These are the long wavelengths. The red is absorbed and no light is transmitted, so it looks dark black. Let's describe why and how some colors are absorbed. One way is called color center.
11:03
Color centers, or f-centers in German, are defects that cause color by absorption of light and they are most often due to radiation damage or extreme heat. When you heat a material, you create more vacancies in it.
11:22
You know that vacancies in crystals are always stable. There are always vacancies in crystals. There are no perfect crystals in existence. Thermodynamically, all crystals must have vacancies, so no perfect crystals.
11:41
And my advice to you young people, since nature does not allow perfectionism, when you look for a partner, never look for the perfect partner. Thermodynamically, they don't exist. If damaged by radioactive decay, electrons can be removed from their normal sites,
12:03
so radiation or excessive heat, then electrons can be removed from their normal sites and come to rest in a vacancy. And the vacancy is called, in this case, a trap. And the crystals have many different types of electron traps. And so, electrons in specific traps
12:22
absorb only certain range of wavelengths, and if you have several kinds, then several wavelengths can be absorbed. Color that is seen through the gem is a color not absorbed by the trapped electron, obviously.
12:41
And if trapped electrons escape their traps, the color center disappears and the color is removed. So it means that you can take a crystal with a color and anneal it at moderate temperature so as to allow stability. Electrons go back to where they should be, and the color will disappear.
13:01
Let's say a word about the color of diamonds. Diamonds occur in various colors, black, brown, yellow, gray, white, blue, orange, purple, pink, and red. And colored diamonds contain crystallographic defects, including substitutional impurity. This means impurity that replace carbon atoms, substitutional.
13:24
And structural defects, such as vacancies and others, and twins, which are very common in diamond, and cause the coloration. Here are examples of very colorful diamonds, and these are the more expensive diamonds
13:41
because the transparent ones, without color, are in abundance. And these, if found naturally, are extremely expensive, especially if they are large. Diamonds are best in several properties. Diamonds are wonderful materials. Hardness, diamond is the hardest material known.
14:02
Hardest material known. Transparency, diamond is transparent to a broad spectrum. Heat conductivity, diamond is the best heat conductor material. It is four times better than copper in conducting heat. This is amazing. This is why in some languages it's called ice,
14:22
because when you touch it, it's cold. So, excellent heat conductor. Electrical properties, diamond is a good electrical insulator. However, blue diamonds are exception, and are semiconductor due to substitutional, substitutional boron impurities replacing carbon atoms
14:42
with a band gap of 5.5 electron volt. This is a large band gap, but in some cases it may be useful. Diamond is a wonderful material, no doubt. Generations of scientists and alchemists try to find ways to make artificial diamonds,
15:01
and stories were written about it, and people really, really tried to make diamonds. And the first success is attributed to General Electric, in the end of 1954. By the way, they started their work before the Second World War, but the Second World War interrupted,
15:20
and they continued after, and announced that in the end of 1984 that they produced the first high-temperature, high-pressure diamonds, imitating natural conditions in which diamonds are formed in the earth. So they imitated the condition, and succeeded in forming what is known as man-made diamonds.
15:44
This diamond was still expensive, and made in small quantities. Now, wouldn't it be great if you could make diamonds in large quantities, an inexpensive way? Wouldn't it be wonderful if you could have large diamonds inexpensively?
16:02
And here comes a story. And later on, you will see how this story is related to diamonds. At first, it doesn't seem like that. And the story is about polywater. The old generation here know very well about polywater.
16:22
Young generation, I am not sure. So here is the story. 1961, who? Soviet physicist Nikolai Fedyakin from the technological institute of kostroma in Russia. He performs an experiment. He studies properties of water put in narrow quartz capillary tubes.
16:43
Narrow quartz capillary tubes. He put water in them. Why not in glass tubes? Because quartz is not supposed to dissolve in water. So this is why quartz. He puts water in very fine capillary tubes,
17:01
and the result, a new form of water with higher boiling temperature, lower freezing temperature, and much higher viscosity than ordinary water. Hey, when this new water has higher boiling temperature
17:20
and lower freezing temperature, it means that it is more stable than regular water. This is the stable form of water, says Nikolai Fedyakin. But Nikolai Fedyakin works in a remote laboratory and enters Boris Deryagin. Boris Deryagin, a famous chemist in the Soviet Union.
17:43
He is the director of the laboratory of surface physics in the Institute of Physical Chemistry in Moscow. Now this is Moscow. And the large team, more than 25 scientists, take Fedyakin findings and start to work secretly
18:01
on this fantastic new form of water, secretly because it may have some military applications. The experiment, he performed many more experiments, more precise and more careful, and the result, same. We have a new form of water.
18:24
Now, this is unknown to the world, but in 1966, Deryagin travelled to England and talks about anomalous water in the discussion of the Faraday Society in Nottingham. Some of you know about Robin Hood and the Sheriff of Nottingham.
18:40
This is the place. So British scientists from top universities start to study the anomalous water and in 1968, scientists from Ivy League University in the United States study and explain theoretically the anomalous water phenomenon.
19:01
Not only the observations, but now there is a theoretical explanation. And a large number of papers are published explaining the phenomena theoretically and repeating experiments and showing that indeed the Russian results are correct. 1966, sorry, this is a new and most stable form of water.
19:28
From 1969 to 1970, anomalous water, now known as polywater, polymerised water, hit the general media and the public. Now it is in the newspapers and the result is panic.
19:43
Why panic? Because the newspaper writes the following. Hey, if this polywater is stable form of water, if you drop a drop into the ocean, the ocean will polymerise and this is the end of life on Earth.
20:00
Hey scientists, what are you doing? Beware, you are playing with the future of life on Earth. 1973, polywater is found to be contaminated water.
20:20
Many people give many explanations how contaminated they are, but I believe in one scientific explanation. You see, quartz does not dissolve in water, only a little. And when you have a ratio of surface to volume, which is extremely high in a fine capillary,
20:42
a lot of surface and a very small amount of volume, then the little amount causes high concentration and polywater is just water with silica and water with silica have other properties.
21:02
Okay, polywater epilogue, shame, remember? Ivy League University in the United States, not only many other institutes, NBS, where I made my discovery, was involved, yes. And measures taken to prevent such fiasco in the future,
21:24
what are the measures, how? Internal peer review before articles are sent for publication. When I wanted to send my quasi-crystal paper, the first one, it was from NBS. The first question, first I had to submit it to peer review,
21:42
internal peer review. And the question came immediately, is it not polywater again? We had to promise them that the evidence are very good and I studied it many times and everything is fine. And then they let us send it and they were afraid that it is indeed polywater again.
22:04
This is the end of story. How is it related to diamond? Aha, okay. Many scientists do not like Deryagin anymore. They don't like him. And then several years after polywater fiasco, Deryagin comes with an announcement of a CVD process,
22:24
chemical vapor deposition process, to create diamonds for methane and hydrogen mixer. Give me methane, give me hydrogen, I will make you diamonds. First reaction, Deryagin go home. We had enough of you.
22:41
Ridicule rejection. However, this time Deryagin was right. And he was a great chemist by the way. And the CVD process can create polycrystalline diamonds in large quantities for a reasonable price. Gem quality diamonds deposited on diamond seeds
23:01
and industrial polycrystalline diamonds deposited on other subsets are made by CVD process. If you want a plate for dinner made of polycrystalline diamonds, you can have it. No problem. Any size, whatever you want. It's available. So, now we have a way to make large volume of synthetic diamonds.
23:28
What can we do with these diamonds? Not very much. Why? Well, for window purposes there are better materials.
23:40
Sapphire is better than diamond. If you want to put it on for military purposes when there is great heat and friction, doesn't work. If you want to coat cutting tools with it, it works. And it works only for aluminum.
24:02
You cannot cut steel with a cutting tool which is covered with diamond. Why? Because the hot steel that you cut will eat away the carbon and the diamond will very quickly disappear. So, not very much we can do with it. So, this is the end of my talk.
24:22
And this is me. And my family. Thank you.