 In your reading about rock crystal in the Islamic tradition, you would have seen one of these photos and read briefly about early rock crystal lamps prior to the Islamic period. So these are works that were made in the Near East prior to the rise of Islam. So prior to about the 6th century, 6th, 7th century CE, this is a fish shaped lamp and you can see it reflects that traditional association between rock crystal and water by depicting a fish and then of course it takes advantage of the light magnifying properties of rock crystal to be used as a lamp. And as I understand this lamp would have been used of course any open flame would have been particularly dangerous and hanging open flames were especially dangerous but what they would do is they would fill the basin that you see here on the underside of the fish with water and then there would be a thin film of oil on the top and that's what would actually be lit. You could also have sort of a vial of oil inside of a basin of water. And so the idea is if this gets knocked down the water is going to extinguish the flame thus preventing a very dangerous fire situation. Here's another early lamp and here we have sort of a bowl shape of rock crystal with projecting relief sculpture that is sculpture that is attached to the surface that it's on as opposed to sculpture in the round and these sculptures depict fish and shellfish so I think you can see the spiraled shell that is just slightly to the left of center to the left of that you can see the tail and part of a fish that's kind of turning on one side of the lamp and then there are other sea creatures projecting on this. This particular lamp is set within a later gold frame that would have originally had jewels on it and like the previous lamp these are both in the treasury of San Marco in Venice. I was given the permission to photograph there which is kind of unusual, I was very lucky. But this again kind of continues in that association between rock crystal, pure water, celestial water and light and that's something that we're going to see taken over by the Islamic religion and pushed in a very particular way just the way that the Christians used similar associations between light and water and rock crystal in their works of art and particularly purity and rock crystal. Just briefly here's another view of that same lamp except we're looking at it at about a 90 degree angle from where we were before and here you can see that fish I was talking about directly ahead of us. So it is kind of swimming upside down it looks like with its tail out and apparently some lamps were actually placed as bowls upside down. I'm not exactly sure precisely how these worked but this one might have been used that way originally and then as you know it is now in a later framework and you can see that framework a little bit better in this slide. Here's an actual Islamic lamp and this one was not made for a mosque but it was in fact made for a royal patron and the inscription in Arabic around the top of it refers to the patron and wealth and prosperity. Again the framework holding this is much later it was brought to Venice and turned into a vessel for the church a covered cup but here you can see again that wonderful clarity of the rock crystal you can see I think you can appreciate just how expensive this work must have been because it's an almost flawless piece of rock crystal with only a few small imperfections running through it and you can I think you can appreciate when you look at the details I have on the right the almost liquid quality of this very hard brittle material. In the video interviews that you watched with me discussing techniques with Elise Moreiro an experimental archaeologist at Oxford one of the things that she was describing was the way that rock crystal ewers which is what we're going to be looking at next were formed and once the general overall shape of the ewer was formed then it would be drilled into to start to hollow out the actual vessel and so the slightly blurry diagram that I have on the left shows you how a tubular drill and this could be something as simple as sort of a copper pipe that you would get in a closed or home depot today would be used to drill a tubular opening into a large piece of rock crystal. At the top right what you're seeing are actual examples of tubular drills used in India in the rock cutting industry there and then the diagram that you see on the right shows a tubular drill being used and what you need to know is that it's not the metal that's doing the work here but instead it is some sort of a grinding abrasive powder and in the Islamic world in the 10th century CE when works like this were being made that could have been something as simple as sand which is silica or it could have been something a little harder like corundum which is a type of garnet it's possible perhaps that they could have used diamond powder that's really more of a modern grinding medium and in fact in her experiments researching the techniques Elise Moreiro actually tried different types of grinding powders and was able to identify the marks and different types of powders used for both grinding and polishing and so that's why I listed the three possibilities of sand, corundum or a diamond powder Historically and even today artists tend to be very frugal about their materials particularly when they're expensive and in the Islamic world we have no exception the fatimid crystal workers who made works like the Ewers were going to see took those tubular cores and used them to make smaller vessels and that's what I'm showing you here in the center and right of this particular slide they would make little bottles out of those tubular pieces that were cut out of larger vessels and those in turn would be drilled with a tubular drill and then you would get something that could turn into an even smaller bottle or possibly a bead for jewelry the central bottle is very much like the types of bottles that you might purchase in Fatimid Egypt back in the middle of the 10th century and on the right you can see another such example and here it's been incorporated into a reliquary cross in a German treasury a lot of the surviving vessels that we have from Fatimid Egypt were brought into western treasuries in many cases by crusaders sometimes they were given as gifts sometimes they were souvenirs from people who traveled widely and then purchased them and gave them later to churches but these were considered precious in the Christian tradition because of all of those associations with rock crystal and they were reused here's a great few views of one of those rock crystal bottles and I'm showing you some detailed views of it so that you can see where the core of it was drilled out you can get a sense from my fingers here in my gloves that it's slightly thicker than a human thumb and so you could actually get a much smaller bottle one that might be sort of pinky finger sized out of the core from this and then from that small bottle you might be able to take cores and cut them into beads you can also see some of the really delicate carving on this particular bottle and I want you to recall what Elise was telling us about the ways that these pieces would be cut and we'll talk about that in a moment here are two of the rock crystal ewers that belong to a group of rock crystals from Fatimid Egypt that are considered the Magnificent Seven they are of unparalleled workmanship and take a look at these each one of them stands about 10 inches tall and is just worked with so much precision and detail you have relief that strongly stands out from the surface behind it you have really elaborate scroll work and designs the piece on the left that you see is in the Louvre Museum in Paris and it came into the Treasury of Saint Denis a very wealthy Abbey church outside of Paris probably in the 12th or 13th century the piece on the right is in the Treasury of Saint Marco in Venice and most likely came to Venice during the Crusades we're looking at a third you were here this one's in the Victorian Albert Museum in London and on the right I have a diagram that Elise Moreiro made showing what would have been sort of the first working version of something like this initially the rock crystal artist would have cut and drilled into the rock crystal on the surface sort of the general areas that would be raised up in relief against the regular surface of the ewer so these are the so-called eyelets that stand proud of the surface of the crystal and stick out a little bit more I hope this slide maybe clarifies things for you and you might want to go back and re-watch some of the video clips with Elise Moreiro discussing these techniques after you finish this video here's a close-up I made of the ewer that's in Saint Marco in Venice and I just want you to notice how much we have here we're looking at sort of the feet and the tail of that lion on the ewer and I want you to notice how much that projects from the surface of the crystal so we truly do have some fairly high relief and then that's carved into using a grinding wheel to give dots and lines and show areas of contour and pattern on that particular lion we're back to the general view of the ewer in Saint Marco in Venice and a detail view showing the head of that lion and again you can see just the sheer quality of workmanship here and all of the fine details and just imagine the difficulty and the expertise that this would have required because we're talking about again probably brittle medium one that is very hard to find in these really nice size chunks that are really really clear and without many major imperfections in them this particular piece of crystal is really brilliantly clear and one wrong move and the entire thing would be lost think about how many failures the artist must have encountered along the way before he or she became a master of this material this is the last example that we're going to look at and this is another ewer that is also in Saint Marco in Venice and it's also part of that group called the Magnificent Seven this particular one features rams on it and I want to make a little note here about how these objects would have functioned as far as we can tell from the inscriptions on the surviving ewer many of which do have inscriptions these were meant for royal use so they probably would have been used to hold water or wine or some other type of liquid and again that association between liquid and light and crystal would come into play in that case and of course the wonderful qualities that rock crystal has when responding to color of course in the Christian world when works like this were captured or brought into church treasuries by whatever means these would be used as precious vessels to hold substances like holy oil possibly wine for communion possibly holy water and also in the case particularly of the smaller vessels small pieces of the saints called relics and relics were very very important to the Christian tradition in the Middle Ages we're going to close with just some closer looks at this ram on this ewer I want you to notice all of the linear detail that decorates this relief image of a ram you can see lines delineating the horns giving us a sense of fuzzy hair on the muzzle and on the chin dots giving us the impression of curly wool on the body for example and we also have similar lines on some of the plant forms here in this detail we've zoomed in even a little bit closer and this is that plant form kind of close to the ram's head and what I'm showing you in the detail view is a microscopic image that was made when Elise Moreira was doing her research and in it you can see how the grinding wheel was used to cut these lines and some of that overlap you can see is just a product of using a wheel of a particular depth or breadth when grinding I hope you appreciate these amazing vessels as much as I do I think they're truly spectacular