 In module 2, we're going to be learning about lapis lazuli, which forms the blue basis of the pigment ultramarine. So lapis lazuli, in fact, is a rock that is made up of a cluster of minerals that co-occur or that form together under the same conditions. The blue mineral is the one that we're really interested in, in terms of the creation of blue pigments. And that one is called lazurite. Lazurite is a somewhat complex sodium-calcium-aluminum silicate sulfide. The lazurite will be found associated with pyrite, which is an iron sulfide, and white calcite, which is a calcium carbonate. These three minerals commonly grow together under metamorphic conditions that we'll talk about a little bit later. It's also worth noting that very often what we refer to as lazurite in lapis lazuli is actually the mineral hawain, which is a very closely related mineral. It has the exact same chemical composition as the lazurite does, except instead of containing sulfur, pure sulfur sulfide, it contains sulfate. So in order to process a rock, lapis lazuli containing three different minerals, only one of which we are interested in for the purposes of making our blue pigment, the first thing we would do is break down the blue mineral into chips, as we see here. And then those chips could go into a mortar and pastel, as seen here, and ground in order to make a blue powder evidence of which you can see here. And here's some that we've made. Once it is very, very purified, you can get a really brilliant, intense blue from lapis lazuli. And this is as close as you can get to the pure lazurite mineral. And this is a process that requires two weeks of hard work, and you only get a yield that represents about two to four percent of the actual stone by volume. So this is part of the reason that this was such an expensive pigment in the ancient world and well into the early modern period. It wasn't until the 19th century that an inexpensive alternative was found that could be created in a laboratory. And there are particular qualities we'll explore in this unit that make this ultramarine blue pigment so precious and so prized. There was a great deal of meaning associated with the blue, and the rocks themselves were also used, particularly in the ancient world, in the ancient Near East and by the Romans, perhaps also by the Greeks, for small-scale sculptures and pieces of jewelry, for example. And the stone was rare enough, it had to be mined in fairly remote locations, primarily in present-day Afghanistan where it's still being mined. And so the brilliant color and the rarity also made it quite expensive and highly valued. So we'll be exploring how it was used both as a pigment and also as a sculpture medium in the art portion of this unit.