WEBVTT Kind: captions Language: en 00:00:00.000 --> 00:00:06.480 This video has been sponsored by Nord VPN. Right  now they're offering 75% off 3 year plans, as   00:00:06.480 --> 00:00:14.610 well as one month free, which you can get by going  to nordvpn.com/nilered. As a kid I can sometimes   00:00:14.610 --> 00:00:19.800 remember looking through dirt, and finding little  bits that looked almost like gold. And almost   00:00:19.800 --> 00:00:24.330 every time, I would get really excited thinking  that I was rich or something, only to be quickly   00:00:24.330 --> 00:00:29.520 shut down, and told that it was worthless fool's  gold. At the time I kind of just accepted that   00:00:29.520 --> 00:00:34.920 answer, and I threw away what I had found, without  really questioning much. What I didn't know though   00:00:34.920 --> 00:00:40.230 was that despite it being way less valuable than  gold, it was still a really interesting compound.   00:00:40.230 --> 00:00:46.440 The mineral name for fool's gold is pyrite or iron  pyrite, and its chemical name is iron disulfide.   00:00:46.440 --> 00:00:53.460 It's chemical formula is pretty simple just FeS2,  but what makes it really cool, is the different   00:00:53.460 --> 00:00:58.560 ways that it can crystallize. The appearance that  it ultimately takes on, will depend heavily on the   00:00:58.560 --> 00:01:03.330 environment that it was formed in. Some important  factors that affected, are things like purity,   00:01:03.330 --> 00:01:10.080 time, pressure and temperature. For example  pirate from a certain region in Spain, tends   00:01:10.080 --> 00:01:16.440 to form these oddly perfect looking cubes, which  honestly still kind of look fake to me. Their size   00:01:16.440 --> 00:01:21.510 and distribution can also vary quite a bit, and  some crystals can get really big like this one.   00:01:22.710 --> 00:01:27.240 The base unit cell that builds the pyrite  crystal is cubic, and under these circumstances,   00:01:27.240 --> 00:01:34.410 the macroscopic crystal that formed, was cubic as  well. However, impurities and the other conditions   00:01:34.410 --> 00:01:38.760 that I mentioned earlier, can alter how these  units build on each other, and it can affect the   00:01:38.760 --> 00:01:43.710 final appearance. So depending on where you are in  the world and what the geological conditions are   00:01:43.710 --> 00:01:49.740 in that place, it can look quite different. For  this video, I'm gonna be focusing on pyrite, but   00:01:49.740 --> 00:01:56.160 I did want to mention that it is possible, for the  iron disulfide to have a non cubic unit cell. It   00:01:56.160 --> 00:02:01.050 can instead be something called orthorhombic, and  when this happens, it forms a different mineral   00:02:01.050 --> 00:02:06.870 called marcasite. This one's a lot more brittle  though, less stable, and has a different color. In   00:02:06.870 --> 00:02:12.630 any case, now that we know a bit about what fool's  gold is in general, I want to dive a bit more into   00:02:12.630 --> 00:02:18.630 its physical and chemical properties. So to start  off just in appearance and feel, I think it's   00:02:18.630 --> 00:02:24.240 really similar to metal, and color wise, it can be  close to that of gold, and it's also often found   00:02:24.240 --> 00:02:30.000 in the same area as gold, so it's not surprising  that they can sometimes get mixed up. The biggest   00:02:30.000 --> 00:02:34.530 difference though, is that gold is never found  as these sharp and highly ordered structures,   00:02:34.530 --> 00:02:40.350 and it's usually just found as an amorphous chunk  like this. And another major difference is that   00:02:40.350 --> 00:02:46.260 gold is really soft and malleable, whereas pyrite  is really hard and brittle. So if it's hit with   00:02:46.260 --> 00:02:50.880 something like a hammer, the pirate would shatter  into pieces, whereas the gold, would just get   00:02:50.880 --> 00:02:57.240 flattened. Also in terms of its density it's only  around 5 grams per cubic centimeter, whereas gold   00:02:57.240 --> 00:03:03.900 is about 19.3. With small quantities it might be  hard to tell, but once you get a decent amount of   00:03:03.900 --> 00:03:09.090 the pyrite, the weight difference is pretty  obvious. So when a big chunk is found it's   00:03:09.090 --> 00:03:13.650 relatively easy to tell a difference, and it's  only really an issue when you have lots of small   00:03:13.650 --> 00:03:20.850 bits. For example here, in a clip that I found on  YouTube, it really does look like gold. However   00:03:20.850 --> 00:03:25.440 this was only because the really shiny pyrite  was reflecting a lot of the light from the sun,   00:03:25.440 --> 00:03:30.900 and making it hard to tell its color. Once he  moved to the shade though the brassy yellow color   00:03:30.900 --> 00:03:36.720 of the pyrite became quite evident, but the color  of the gold stayed the same. His other simple test   00:03:36.720 --> 00:03:41.250 was based on the fact like I mentioned before,  that the density of pyrite is way less than that   00:03:41.250 --> 00:03:46.560 of gold. Just by gently swishing around the  water, the heavier gold is able to stay put,   00:03:46.560 --> 00:03:52.800 but the lighter pyrite is moved around. From its  overall metallic and shiny look, a lot of people   00:03:52.800 --> 00:03:58.320 would think that it's conductive and, well they're  right it kind of is. It's not nearly as conductive   00:03:58.320 --> 00:04:03.810 as a proper metal though, and it's classified  as a semiconductor. In general, semiconductor   00:04:03.810 --> 00:04:08.340 materials are used pretty extensively in the  electronics industry, and it has been suggested,   00:04:08.340 --> 00:04:15.090 that pyrite might have some use there as well.  Currently I think the major use of it related to   00:04:15.090 --> 00:04:20.970 things that are electronic, is in non-rechargeable  energizer lithium batteries. In this battery,   00:04:20.970 --> 00:04:26.040 one of the electrodes is the lithium itself and  the other one, is made by coating iron disulfide   00:04:26.040 --> 00:04:32.010 on a thin layer of aluminum. Okay so now for the  fun part, where I get to play around with it,   00:04:32.010 --> 00:04:36.990 and learn more about its chemical properties. It  would have been insane to sacrifice my really nice   00:04:36.990 --> 00:04:43.020 cube so instead, I bought a bunch of ugly ones  from eBay. I really don't remember exactly how   00:04:43.020 --> 00:04:49.680 much it cost, but it was quite cheap, and probably  only around $20 for the whole bag of them. For   00:04:49.680 --> 00:04:54.360 the first test, I just put a small amount of  concentrated hydrochloric acid, on one of the   00:04:54.360 --> 00:04:59.190 pieces. I let it sit there for a few minutes,  but it didn't look like much was happening.   00:04:59.190 --> 00:05:05.760 There should have been a reaction going on, but I  just think it's really slow. The iron disulfide is   00:05:05.760 --> 00:05:12.270 FeS2, but I thought that it might react faster  if I converted it to just FES. This can be done   00:05:12.270 --> 00:05:17.070 pretty easily by just heating the pyrite to its  decomposition temperature, which starts at around   00:05:17.070 --> 00:05:23.760 540°C. To do this, I just carefully shot it with  a blowtorch until it looked like the surface was   00:05:23.760 --> 00:05:29.370 turning black. Some pieces of pyrite also started  cracking off, but I'll talk about that in a bit. 00:05:33.330 --> 00:05:39.000 When it cooled down, I added the HCL  again and the effect was very subtle,   00:05:39.000 --> 00:05:44.640 but it was there. Like last time, I left  it for a few minutes and when I removed it,   00:05:44.640 --> 00:05:50.100 almost all of the blackness had disappeared.  The HCL had also taken on a yellow color,   00:05:50.100 --> 00:05:55.290 which you can see on the paper towel. So the major  thing that happened here was a reaction between   00:05:55.290 --> 00:06:01.470 the black FeS that I made, and the hydrochloric  acid. This lead to the formation of Fe(ii)Cl,   00:06:01.470 --> 00:06:07.470 as well as hydrogen sulfide gas. The amount that  was reacting here was so little though that it   00:06:07.470 --> 00:06:14.040 wasn't really possible to see any gas coming off.  However I wanted the effect to be much clearer so   00:06:14.040 --> 00:06:20.100 I decided to try heating the pyrite more, and to  convert as much as I could to the FES. Initially   00:06:20.100 --> 00:06:25.530 it looked decent and the whole surface was turning  black but then suddenly, pieces of it started to   00:06:25.530 --> 00:06:31.320 shoot off. I'm not 100% sure what caused this, but  I think it is a direct result of the decomposition   00:06:31.320 --> 00:06:38.760 of the FeS. In order for it to break down to FES,  it needs to kick off a sulfur. It's fine if this   00:06:38.760 --> 00:06:43.470 happens on the surface of it because the sulfur  just boils off, and then burns in the air to make   00:06:43.470 --> 00:06:51.030 SO2. However if this happens in the cube, there's  no place for the sulfur gas to go. So I imagine   00:06:51.030 --> 00:06:55.740 that it starts building up pressure, and it  eventually gets to a breaking point. To a certain   00:06:55.740 --> 00:07:01.260 extent there's also probably some water mixed into  the mineral, which also can cause it to explode. I   00:07:01.260 --> 00:07:07.140 continued heating the large piece that remained  and initially some pieces did come off of it,   00:07:07.140 --> 00:07:12.900 but eventually it stopped. I'm not exactly sure  why it stopped breaking apart, but I'm assuming   00:07:12.900 --> 00:07:18.390 that it was somehow able to release some of the  gas pressure. I kept heating it until most of   00:07:18.390 --> 00:07:24.150 it had become red-hot, and then I let it cool  down. As it cooled, the surface of it slowly   00:07:24.150 --> 00:07:31.500 got oxidized by oxygen in the air to make what I  assumed was red Fe(iii)2O3. When it eventually got   00:07:31.500 --> 00:07:35.370 to room temperature, I thought that it was pretty  interesting, because it didn't look like the   00:07:35.370 --> 00:07:41.010 fool's gold at all anymore. There was absolutely  no goldish yellow color left, and it was all just   00:07:41.010 --> 00:07:47.100 black and red. Like I just said, I think the  red stuff was Fe(iii)2O3, but I'm not sure   00:07:47.100 --> 00:07:53.730 if the black stuff was FES, or Fe(ii)O. I tried  testing it again, by just adding some hydrochloric   00:07:53.730 --> 00:07:59.100 acid to the surface of it, and it kind of just  soaked it up. If you recall from before though,   00:07:59.100 --> 00:08:04.860 when I tried this with the intact pyrite, the acid  just sat there. So apparently as it decomposed,   00:08:04.860 --> 00:08:10.260 it got a lot more porous. I broke it apart  with a hammer, and what I thought was cool,   00:08:10.260 --> 00:08:15.900 was that it was possible to see all the different  layers. On the outside was the fully reacted and   00:08:15.900 --> 00:08:22.380 oxidized stuff, but then right underneath it was  a layer of black FeS. Then just below that was   00:08:22.380 --> 00:08:28.890 the still fully intact FeS2. I really thought that  the heat penetrated much deeper, but apparently it   00:08:28.890 --> 00:08:35.340 didn't. Onto this I tried adding the hydrochloric  acid again, and it worked a bit better. It was   00:08:35.340 --> 00:08:39.990 possible to see a small amount of bubbling, but  it still wasn't as good as I would have liked it   00:08:39.990 --> 00:08:46.650 to be. To get it to react vigorously, I would need  to convert a lot more to the FES. And to do this,   00:08:46.650 --> 00:08:51.870 I first had to crush it up. This really isn't  very hard to do though, because the pyrite is   00:08:51.870 --> 00:08:57.840 actually quite brittle. So I just added some of  it to a mortar, and started bashing it. This was   00:08:57.840 --> 00:09:02.490 what I had after a few minutes, and I probably  could have crushed it a bit more, but I figured   00:09:02.490 --> 00:09:07.650 this was good enough. This was all added to a test  tube, and I did my best to flush it with nitrogen. 00:09:12.000 --> 00:09:18.000 Then just like all the other times I blasted it  with a blowtorch. The reason I used the nitrogen,   00:09:18.000 --> 00:09:22.890 was that I hoped without any oxygen present, the  sulfur would be able to come off, and knock it   00:09:22.890 --> 00:09:29.310 immediately converted to SO2. After only heating  it a bit, it all started turning black, and I   00:09:29.310 --> 00:09:33.750 could see that there was a gas being released  from the powder. Because of the background it   00:09:33.750 --> 00:09:38.610 was hard to see, but there was also a white  vapor that had filled the tube. At the time,   00:09:38.610 --> 00:09:43.710 it didn't occur for me to test it, but it was  almost definitely sulfur maybe along with a   00:09:43.710 --> 00:09:49.830 bit of water vapor. What I think is cool, is that  industrially, pyrite is used in a very similar way   00:09:49.830 --> 00:09:55.470 to this, to generate elemental sulfur. Depending  on the purpose, the sulfur can be kept as is,   00:09:55.470 --> 00:10:00.900 or can also be converted to SO2 for  the paper industry, or even to SO3,   00:10:00.900 --> 00:10:07.740 to make sulfuric acid. When I felt like most of  it had converted to FES, I stopped heating it,   00:10:07.740 --> 00:10:12.000 and I let it cool. I probably should have  refilled the tube with nitrogen though,   00:10:12.000 --> 00:10:17.910 because as it cooled, the surface was oxidized  and it turned red. I figured this was fine because   00:10:17.910 --> 00:10:23.130 most of it was still black, but then I mix things,  and saw there was still a whole bunch of pyrite.   00:10:23.130 --> 00:10:27.900 I apparently had the same issue as before, where  it only really converted the stuff on the outside,   00:10:27.900 --> 00:10:33.570 and the stuff in the center, was more or less  intact. This time though, I thought I still   00:10:33.570 --> 00:10:38.520 made more than enough, so I continued on with  the testing. When it got to room temperature,   00:10:38.520 --> 00:10:44.040 I dumped it all onto a dish, and it honestly  kind of looked the same. Nonetheless I took a   00:10:44.040 --> 00:10:49.050 small sample of it, and I placed it onto another  dish, and tried adding hydrochloric acid again. 00:10:51.330 --> 00:10:58.170 This time the reaction was way more vigorous,  and a gas was definitely being produced. H2S   00:10:58.170 --> 00:11:04.320 is extremely potent, and even in small quantities  it smells like rotten eggs. So a very simple test   00:11:04.320 --> 00:11:08.970 for it, is technically just to try and smell  it. This was all done in my fume hood though,   00:11:08.970 --> 00:11:14.190 which apparently worked quite well, because I  didn't smell anything. The only real way for me to   00:11:14.190 --> 00:11:19.710 smell it would be to bend over and to get really  close to it. The problem with this though, is that   00:11:19.710 --> 00:11:26.490 H2S is also super toxic around the same level  as cyanide gas, so I wasn't too excited about   00:11:26.490 --> 00:11:32.730 trying to take a breath of it. The much smarter  thing is to instead use test strips. These are   00:11:32.730 --> 00:11:39.330 made pretty easily by soaking paper in a solution  of lead acetate, and then letting it dry. Now if   00:11:39.330 --> 00:11:45.450 I was in fact making H2S, then the lead acetate  on these strips, should be able to react with it,   00:11:45.450 --> 00:11:53.340 to make black PbS. And when I did this, that was  exactly what happened. I was making the H2S here   00:11:53.340 --> 00:11:59.550 mostly as a demo, but in general it is a useful  chemical. In the lab, it's usually produced the   00:11:59.550 --> 00:12:07.260 same way, where a strong acid is reacted with FeS.  However the FeS is rarely made from pyrite, and   00:12:07.260 --> 00:12:13.680 it's usually either purchased, or made directly,  by reacting iron and sulfur powder. It leads to an   00:12:13.680 --> 00:12:18.840 extremely exothermic reaction, and this is a clip  from one of the first videos that I ever posted   00:12:18.840 --> 00:12:23.520 to this channel. The videos that I made back then  were totally different, but if you're interested   00:12:23.520 --> 00:12:29.130 in checking it out, there's a link in the  description. In any case I think that's about it,   00:12:29.130 --> 00:12:34.020 pyrite might not be as nearly as valuable as  actual gold, but I think it has enough of its   00:12:34.020 --> 00:12:39.900 own unique properties and uses, that it more than  makes up for this. And honestly, I think the cheap   00:12:39.900 --> 00:12:44.130 price is actually a good thing, because it means  that most people can buy it relatively easily.   00:12:44.130 --> 00:12:49.560 For example, I think the large cube sample that  I have, is one of the coolest things that I own,   00:12:49.560 --> 00:12:56.220 but it only cost me something around $100. In  Canadian dollars, that's about two grams of gold,   00:12:56.220 --> 00:13:02.280 which is not only not very much, but also nothing  really impressive to look at. In any case,   00:13:02.280 --> 00:13:07.540 this was the first video that I did on a mineral  and I had a lot of fun doing it. I definitely plan   00:13:07.540 --> 00:13:12.070 to do this again with another mineral, so in the  comments, let me know what you'd like to see. I   00:13:12.070 --> 00:13:19.060 ended up getting really behind schedule editing  this video, so I'm probably gonna be posting it   00:13:19.060 --> 00:13:24.490 from the airport, on my way to Japan for vacation.  To do this though, I'll have to connect to the   00:13:24.490 --> 00:13:30.610 public airport Wi-Fi, which isn't really secure,  and kind of makes me nervous. However luckily,   00:13:30.610 --> 00:13:36.430 services like Nord VPN exist, which allow me to  keep my data safe, by encrypting everything that's   00:13:36.430 --> 00:13:42.490 sent, and received by my computer. This way, I can  log into all my accounts, or even buy things with   00:13:42.490 --> 00:13:47.950 my credit card, without worrying about getting my  info or passwords stolen. On top of this though,   00:13:47.950 --> 00:13:53.380 there are a whole bunch of other benefits of  Nord VPN. For example, it has a built-in add   00:13:53.380 --> 00:13:58.240 and malware blocker, and it also anonymizes  you on the internet, making it difficult to   00:13:58.240 --> 00:14:04.030 track or spy on your activity. What I especially  like, is that they have a super easy to use app,   00:14:04.030 --> 00:14:09.850 that works on all mobile devices, as well as  laptops and desktops. All I need to do is just   00:14:09.850 --> 00:14:15.130 click one button, and it's done automatically.  There is also the option to do it manually though,   00:14:15.130 --> 00:14:20.530 and you can choose from one of their over 5,000  servers, around the world. So with that being   00:14:20.530 --> 00:14:26.710 said, I've been using Nord VPN for about a year  now, and I highly recommend it. Also right now,   00:14:26.710 --> 00:14:31.900 they're offering a great deal, that gives you  75% off their three-year plan, as well as one   00:14:31.900 --> 00:14:38.560 extra free month. You can get this by going to  nordvpn.com/nilered, or by clicking the link in   00:14:38.560 --> 00:14:44.500 the description. As a side note, some of you might  be wondering why I'm posting the video on the way   00:14:44.500 --> 00:14:50.710 to Japan, and not when I get there. My answer to  this is kind of simple, where A I don't really   00:14:50.710 --> 00:14:56.230 want to be working on videos once I get there,  and B I just think it could be fun. I'm gonna be   00:14:56.230 --> 00:15:00.640 having a 14 hour plane ride between Minnesota  and Tokyo, and I just thought that it could   00:15:00.640 --> 00:15:20.440 be interesting, to buy Wi-Fi and to answer your  comments from the air. As usual a big thanks goes   00:15:20.440 --> 00:15:26.530 out to all my supporters on Patreon. Everyone who  supports me can see my videos at least 24 hours   00:15:26.530 --> 00:15:32.530 before I post them to YouTube. Also everyone  on Patreon can directly message me, and if you   00:15:32.530 --> 00:15:36.460 support me with five dollars or more, you'll  get your name, at the end like you see here.