 In this unit, we talked about the solid solution of garnet. So a solid solution is a kind of mineral that can have a range of compositions within certain set boundaries. So the, for example, the proportion of silicon to oxygen always remains the same, but then we can have varying amounts of things like magnesium and calcium and iron, making up the chemical composition of the particular garnet that we're looking at. Most of the garnets that you see before you hear are from the pyrope almondene family of garnets, which are magnesium and iron-rich garnets. And these will grow in many different kinds of metamorphic rocks, with more iron-rich garnets growing in more sedimentary, metacetimentary rocks and more magnesium-rich garnets growing in more metavolcanic rocks or metabasaltic rocks, like this particular one from War Mountain, where you can see the nice red pyrope-rich garnet here. Many of the physical properties of garnet then relate back to this variation in the chemical composition of the specific solid solution of each individual garnet. So the hardness can vary from about six and a half to seven. The density of the garnet will vary depending on the mass of the different elements that make it up. The color can vary by quite a bit. And again, these are all from the same family of garnets that give us reddish, brownish, blackish garnets. But in other compositional categories of garnets, we can get green, grossular garnets. We can have pink, spesartine-rich garnets. We can have orange or purple or black. Really, any range of colors and various physical properties are possible. And it all comes back to the different chemical elements that come together within that set structure of garnet in order to create each individual garnet mineral we see. In art, although we do have other colors of garnets being used, what is particularly prized and what shows up in classical and medieval literature about garnets tends to really focus on the sort of blood-red qualities of the garnet. And again, something like this looks black to the camera, but when cut into very thin segments, you get a sort of translucent reddish stone. And in order to take advantage of this translucent, artists beginning with ancient Greece and well into the early Middle Ages and later Middle Ages would place this stone against a reflective background. So for example, thin segments of garnet would be placed against a patterned gold background. And we're talking about something that would be maybe sort of 0.3 millimeters thick. And so you can very clearly see through a garnet like that, it's sort of glass-like and transparent at that thickness. And then you can see patterned gold kind of reflecting through. In the ancient world, they tended not to use thin segments, but rather carve more sort of rounded shapes, work them into rounded shapes with the garnets or actually make small sculptures. But again, it tended to be paired with gold in order to use that reflection, that reflectiveness to advantage. And we're going to be exploring the different ways in which garnet would be used as a luxury material in the ancient and medieval world.