Emory Students Visit ColleVilca Crystal Factory to Understand Hand Blowing Crystal

Last Thursday, June 4, the Emory Chemistry students visited ColleVilca, an Italian crystal factory located in the Chianti area of Tuscany. We learned how hand-blown crystal was made and formed into different products, varying from animal figurines to wine glasses. In the market of glass and crystal blowing, there are certain standards that determine what is glass and what is crystal. What we label as crystal is actually lead crystal, in which lead oxide comprises a quarter of the material, which is predominantly silica (SiO₂). Lead glass has only 18% lead oxide. Lead oxide allows the crystal to sparkle unlike glass with lower lead content. A fun way to detect crystal is to flick a wine glass and you should hear a very long lasting and high frequency ringing tone. ColleVilca takes pride in that it only creates crystal products.

After explaining the procedure to us, the factory workers demonstrated their crystal blowing techniques.  First, molten crystal is collected on the blowpipe from the furnace, which is thousands of degrees centigrade hot. The blowpipe is cooled under water so it is easy to handle by the blower. The crystal worker constantly spins the pipe in his hands to maintain an even and consistent mass of orange glowing crystal. The worker blows air into the pipe, covering the end in order to expand the molten material around the air bubble. As the worker sits at his bench, he uses handheld tools, such as jacks, paddles, and tweezers, to pull and shape the glass. In order to make drinking glasses, the material is placed in a mold. During the detailing process, the crystal worker may reheat the crystal in another oven in order to guarantee malleability. For various products, more molten crystal is added and shaped during the molding stages. Once the ultimate shape is designed, the product is cut from the blowpipe and placed in a final furnace. This furnace has a series of cooling chambers to reduce thermal stress. This prevents the glass from cooling to rapidly and breaking. Finally, the rough edges are sanded, smoothed and polished, creating safe vertices to sip on and handle.

It was amazing field trip to ColleVilca. I now understand the different between crystal and glass. Also, it was so beautiful to see the skill of the crystal blowers in the performance of their craft. They made every step seem so simple and easy. I was surprised by their lack of safety though, because neither of the workers wore goggles or gloves during the entire process. I guess when you are a master of your craft, you have such a high level of experience and confidence in your abilities. I doubt chemists can take such risks with their work, but research is much different than molding molten crystal.