 Okay, hi I'm Maureen Feynman and I'm Heather McCune-Brune and in this module we're going to be talking about alabaster. Alabaster is another one of those materials that as soon as Heather and I started working together we realized meant slightly different things in geology and mineralogy world versus art history world. So in in art history and the materials that were used for carving there are two different kinds of alabaster. One that's known as Egyptian alabaster or Oriental alabaster right here and that alabaster is made from the mineral calcite. So calcite is calcium carbonate. It has a lot of very distinctive properties. One of the most noticeable is the cleavage, what we call perfect cleavage, these flat planes in three directions with characteristic angles of 60 and 120 degrees. So they make these beautiful perfect rhombic texture or habit shaped crystals here. So calcite is a mineral that has a hardness of three which is fairly soft hardness. If you don't mind saying soft hardness. The the other option in comparison to the Egyptian alabaster would be European alabaster or Italian alabaster and this is what geologists are referring to when they refer to alabaster. This in particular is a material, a rock that is made out of the mineral gypsum. So as opposed to calcite which is calcium carbonate the gypsum is a calcium sulfate and in fact it's a hydrated calcium sulfate so it's got some water in its structure and although the calcite had a moderate hardness of three the gypsum has is even softer it has a hardness of two which means if you'll remember from a previous discussion of Moe's hardness scale that means we can take our hardness three calcite and scratch the hardness to gypsum. Just demonstrating that that the calcite is indeed a bit harder and we'll talk a bit later on about how those differences in properties relate to how these materials are used and how they're worked. Another really cool thing about alabaster is that the crystals that make it up are fibrous in nature. So they're masses of fibrous crystals like a fiber optic wire bundles of these elongated crystals and they transmit light in a way that produces this really neat very cool translucence that alabaster is really in particular known for. Heather do you want to tell us a little bit about how that makes its way into the art? This is a property of alabaster that you see being taken advantage of particularly in ancient Egypt. They use this substance extensively for jars for perfume and decorative bowls and vases and then this becomes one of the favorite materials for canopic jars and those were the jars that held the bodily organs when they were removed in the process of mummification. So the heart the lungs the liver and I think the stomach they took the brain out and threw it away because they didn't think that was important. And if you go to a museum that has a good Egyptian collection that includes alabaster oftentimes they will have vessels like this that are spot lit so that you can see that beautiful banding and I have a wonderful piece here that was brought back from Egypt by Stephen Cox the sculptor that I discussed when we were talking about porphyry and you can see the beautiful patterns in this alabaster. And then the the gypsum alabaster in England was kind of valued because it didn't have a whole lot of interesting patterns to it generally and it was incredibly easy to carve and during the late Middle Ages around the year 1400 there was a sculpture industry in the north of England that just sort of mass produced altarpieces out of alabaster and you can find examples of these pieces all over Europe. It was one of the primary exports.