How Murano Glass was born

Have you ever wondered who was the first person to discover the secret to making glass?

The (more or less legendary) account of this discovery is provided to us by Pliny the Elder in his Naturalis Historia. Pliny explains how the glass was discovered purely randomly by a group of Phoenician merchants a few millennia before the birth of Christ. Camped on the banks of the Nahr-Halu River in Syria these merchants would light a fire using natron loaves (i.e. natural soda consisting mainly of sodium carbonate) and this, mixed with sand and due to the heat generated by the hearth, would have given rise to the first glass. Since ancient times, Soda it is therefore the main fondant used to make glass.

The basic raw material, or vitrifying, was (and remains) the silica sandwhich is currently being taken from the quarries of Fontainebleau.

Another key component of Murano's glass making is the calcium carbonate (better known as limestone) which plays a crucial stabilizing role by lowering the melting temperature of the vitrifying mixture, increasing the chemical resistance of the glass (making it more stable against atmospheric moisture and limiting its surface opacity). Thanks to calcium oxide, the glass can therefore maintain its clarity for longer.

For number lovers... The traditional vitrifying mixture is therefore composed predominantly of a vitrifying, sand (about 60-65% of the total), a fondant, soda (about 20-25% of the total) and a stabiliser, sodium carbonate (about 10-15% of the total).

In addition to these first substances there are others that, although used in smaller quantities, play a very important role...

We're talking about the so-called refiners that added in small doses to the vitrifying mixture promote the release of bubbles from the molten glass and improve their homogeneity; The mattifying used to reduce or eliminate the transparency of the glass; The Dyes (usually metal oxides) used to give color to the glass. Commodities include what is called the glass scrap consisting of glass fragments from processing scraps that were merged again with the other components to create a new mixture. Dulcis in fundo should be included Dyes (such as manganese) used to neutralize the natural greenish color of the glass caused by the presence of iron oxide (an impurity found in raw materials).

All these materials are stored in the so-called poison room where a harmful powder extraction system is installed that prevents the components of the vitrifying mixture from dispersing into the environment.

Once ground and carefully weighed the raw materials are mixed (by means of a cement mixer) to obtain a homogeneous mixture that is in turn put in a single container called albuol.

The vitrifying mixture obtained at this point is poured into crucibles (called Pans) or circular-bottomor or oval containers made of highly refractory material capable of resisting the high temperatures required for melting.

Do you think you've discovered the secret to making Murano Glass? I assure you that you have only learned an infinite silet of the secrets of this noble art... 

 

 

1 comment

Luca Messinese

Wow!! Una storia davvero interessante!

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