 In the first part of this module we talked a bit about some of the physical and chemical properties of the different kinds of alabaster just again to review the Egyptian alabaster being calcium carbonate like this here. One of the things that you'll notice about the Egyptian alabaster is this banding to it. Now I spoke earlier about the fibers that grow in alabaster. The fibers are actually growing perpendicular to these bands and each of these represents a stage of growth. So fibers will grow perpendicular to the growth surface and then at the surface you'll get the terminations of that first set of fibers that gives you some imperfect crystallization. You may end up with some void space, some impurities, or even some a little bit of water getting trapped in there before the new set begins to grow. So that's what gives you the banding there and then again the the fibrous nature of it really gives it that nice light transmission property. This is a little bit harder, has a hardness of three. The European alabaster again being gypsum-based calcium sulfate, hydrous calcium sulfate has a hardness of two which is a little bit softer than your fingernail so you could actually scratch that with your fingernail if you really wanted to. These are very different in contrast to some of the minerals and rocks we've been looking at in the previous weeks. Quartz and garnet with hardness of around six or seven. We've looked at igneous rocks made from silicate minerals also very hard and selected for their hardness and their permanence and their their ability to sort of stand the test of time. Very different. These minerals in fact will dissolve if exposed to the elements particularly rainwater. The acid breaks them down very very quickly. But that softness and the different nature of these materials is very important for how they're used in art and I think Heather's going to give us a little demonstration of the benefits of soft minerals. I want you to see the surface here of this particular block of alabaster. This is sculpture grade alabaster that I purchased from an art supply catalog and I let some of my students in a materials demonstration wail away at it with some sculpture tools and one of the things that makes this very interesting is that for example if we were working with porphyry we would have to work just with something like this punch here and backup marine and simply punch into it and it would if I if I had a piece of porphyry here you would be seeing sparks fly up and I would be wailing away at this much much harder probably enough to actually get this to split very dangerously on us. But what you can do with a piece of alabaster we'll also see this with marble is that you can work at an angle with it and you can get a fineness of detail working with your tools your various chisels and punches that you really can't achieve with a much harder stone like porphyry or diorite and when I had a chance to go to Carara to the marble quarries there I got to try out some tools in a sculptures sculptors workshop and it was pretty exciting stuff I felt very intimidated though.