What is Glass?

What is glass, this is a very common question and one I only know a little about. So, I thought I would do some lookin’.  Scientifically glass is generally soda-lime glass, composed of about 75% silica (SiO2) plus sodium oxide (Na2O) from soda ash, lime (CaO), and several minor additives.  The additives help with viscosity, color, and transparency. Screen Shot 2013-06-24 at 5.31.15 PM Volcanic Lava is technically glass. When cooled we call it obsidian.  This is a natural forming glass which was used in prehistoric times for arrow heads and tools. Screen Shot 2013-06-24 at 5.32.08 PM What we know of as modern, man made glass is credited to Ancient Egypt, somewhere around the early to middle Bronze age.  Amulets and beads have been found which date back to this time. Eventually man figured out a pretty stable recipe for glass which included sand, plant ash and lime.  Around 1500 BC the first vessels were made with hot glass.  It was made by wrapping hot glass around cores of earth and dung.  Once everything was cooled the cores were removed, giving you a hollow vessel.  We still practice something similar with beads and small vessels on the hot torch…. earth and dung are no longer necessary in the technique though. Screen Shot 2013-06-24 at 5.45.33 PM In 300 BC the blowpipe was developed by the Roman Empire.  Molds were invented along with new colors and the use of gold and silver inlays.  During the dark ages Europe lost most of its knowledge of glass making but the Middle East retained that knowledge and expanded on it.  As the Middle Ages came about, glass was back in Europe. Screen Shot 2013-06-24 at 5.40.17 PM   ©2009 Jupiter Images Venice, being situated on the far end of the Adriatic Sea, was part of a trade route from the Middle East into Europe.  Those secrets of glass were retained there and became the center of glass making in the middle ages.  In order to protect the island from fire, and to help maintain a monopoly on the secrets they had learned and developed, the glass industry was all moved to the island of Murano in 1291.  Many innovations and a distinct style was developed on the island. Leaving Murano was punishable by death. Screen Shot 2013-06-24 at 5.30.23 PM Screen Shot 2013-06-24 at 5.34.57 PM Over time techniques were shared and developed throughout the world.  Many regions of the globe have specific specialties and distinct styles. This is a brief overview of the beginning of glass.  I know that after barely scratching the surface of what’s happened in glass, I’m pretty curious.  So, I’m planning on continuing this search and learning more. This is going to take some studying on my part so if anyone has something to contribute, please do!  My plan is for the next post to be about Middle Eastern glass and I’ll follow the development of it from there.

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