 Now, we're going to quickly take a look at the minimal property called luster, and that refers to how the light reflects off the surface of a material. Now, we can do that in this mineral simulation, but honestly, it's not the clearest. This is something that just works better with your eyes when you can take a mineral and sort of turn it under the light to see how it reflects off in different directions. So, we're not going to test every sample, but I'm going to point out just a couple of things. I'm going to start by turning on my light here and picking one of my samples, sulfur, and putting it down underneath the light. Now, what we see here, and even if I go ahead and take a look at it with the magnifying glass, is that although the surface is lighter when it's sitting under the light, there isn't any specific reaction in terms of it reflecting the light. So, this has a dull luster. Similarly, magnetite also has a dull luster. It's lighter underneath it, but again, not a specific reflection off the surface. And these are either called dull or earthy lusters. Now, I want to compare that to say pyrite, and pyrite has a metallic luster. And you can kind of see that here under the sample, but more if I put it under the magnifying glass. And it sort of shows the light passing over as if I was tilting it just slightly. But each one of the surfaces definitely reflects like a metal does. So, it has a metallic-like texture. In comparison, we've got something like quartz. And when I use the magnifying glass here, and it's not super, super clear. But if I were to actually have a piece of this and sort of tilt it back and forth, what I'd see is that it has what we call a glassy luster. So, it gives us a reflection, not like a mirror, not like the metallic surfaces, but more a general reflection like a sort of piece of glass as we're looking through it. The glass you want sometimes like this particular piece of quartz. If you held it up to a light, you might actually be able to see light through it. Now, again, I'm not going to show luster on all of the samples, but just a few of them. And there's just a few little questions in your lab manual about some of these that we've looked at in terms of their luster.