The COLLEVILCA Crystall
This wonderful material has been working its deep and ambiguous charm over man for centuries; crystal separates and displays, it contains while revealing at the same time, a delicate sign pointing towards the path of imagination.
The magic mirror, the ball that shows us the future and Cinderella’s slipper are all made of crystal. A close network of crystalline symbols accompanies our existence. Perhaps the fascination stems from the materials that are used to create it and from their transformation upon contact with fire.
It’s a little like what happened in the laboratories of the initiates who received the Arca Arcanorum, the philosopher’s stone of wealth and happiness.
The history of glass-making is very old and even now covered in the deepest mystery. The Phoenicians and the Egyptians argued for centuries over who had first discovered the art.
A Phoenician story narrates that a group of merchants, returning from Egypt with a large cargo of “natron” (our sodium carbonate), stopped one evening along the banks of the River Belus to rest.
As they could find no stones on which to place the utensils required for the preparation of their evening meal, they used instead some blocks of “natron” and lit a fire nearby that continued to burn for the whole night.
The morning after, the merchants were astonished to see that, instead of the sand of the river and the natron, a strange, shiny and transparent material had been created. The Phoenicians realized at once the importance of the discovery and, in their cities of Tyre and Sidon, organized an industry that produced various objects with this new, shiny material called glass.
The Egyptians also exploited the new discovery. In their burial chambers, built some 4,000 years before the birth of Christ, many amulets and objects made from glass have been found.
The Etruscans and Romans used glass to make many different kinds of vases, bottles, amphorae and perfume bottles, often most delicately decorated.
In Venice, during medieval times, the art of glass making that had begun towards the X th century was developed thanks to the very frequent contacts with the city of Byzantium that for many centuries remained a centre for the production of this precious material. From there, the new art was spread all over Europe.
In the 1600s, while trying to make glass softer to work with, English “alchemists” discovered another type of glass, as pure, clear and bright as a diamond: CRYSTAL.
Glass has been produced in this Tuscan town since the XIV th century as documented.
In 1331 the town of Colle di Val d ‘Elsa resolved to prohibit the sale of wood to the glass furnaces:
…nulla persona possit portare od vendere ad aliquam fornacem Bicchierorum de lignis silve comunis de colle…
Right from the beginning, the activity reached such a level of perfection that its fame quickly spread far and wide. In Florence, such was the aggressive industrial competition from other states towards the end of the XVI th century, that the Grand Duke issued an order on 2nd April 1577, aimed at banning foreign glass from the Florentine State. Given that in Florence, at that time, there were no glassworks that produced tumblers and other containers, it appears evident that the order was made to protect the glassworks of Colle.
The modern glass-making industry, however, began at Colle much later, thanks to the initiative of a few French and German businessmen, later continued by our fellow citizens.
Towards the early 1800s, the Mathis family, originally from Alsace-Lorraine, purchased a part of the old Augustinian monastery in Colle and set up a small glassworks.
The choice of location fell on the “city of Arnolfo di Cambio” thanks to the numerous woods in the surrounding area and the possibility of obtaining the nearby quartz, manganese and barium that are required for the production of glass.
Instead of potash, the ash produced from the combustion of large quantities of wood was used.
The marble from the nearby “montagnola senese” area was then added to obtain a brilliant and precious product. The craftsmen were all French: food and lodging was offered to the master glass makers as well as a high daily wage.
The Mathis family, unfortunate tradesmen, failed in their enterprise and the industry was taken over towards the middle of the last century by a certain Schmid who, thanks to his previous experience, began to manufacture crystal that, after a few years, became very famous. Among his many merits we must thank this German businessman for having taught the work-force of Colle. Local people gradually replaced the foreign craftsmen and began to earn professional recognition all over the world.
The articles produced by the “Fabbrica di Cristalli Giov. Batt. Schmid” were appreciated for the beauty of the material that was made from a mixture of various substances, the composition of which was known only to Schmid, and was distributed on the domestic and many foreign markets.
After the death of Schmid, the industry went through a period of decline only to pick up again when Alfonso Nardi set up his factory.
In 1921, the two existing glassworks, the “Elsana” and the “Fabbrichina”, owned by Filippo Lepri & Co., were joined together in a single factory under the direction of Modesto Boschi, a local businessman, who took the company to commercial and social success. During its most florid period the Boschi Glassworks employed more than 500 workers. Unfortunately, the great industrial concern encountered many pitfalls that in the end caused it to be closed down with the consequent loss of many jobs.
After the failure of Boschi, many factories were set up thanks to the enterprise and the spirit of initiative of many people from Colle who had worked in that factory.
In 1947, the brothers Franco and Mario Brogi, esteemed craftsmen from Colle, went to the Waterford factory in Ireland and the Glass Fabrik Sigenuart in Switzerland, where they experimented with different forms of expression in crystal and were able to compare their own experiences with those of these great European companies.
In 1958, after this fruitful journey, they established the Vilca Crystalworks in Colle di Val d’Elsa.
In 2003, Franco’s son, Giampiero, and Mario’s daughters, Laura, Patrizia and Frida, bought the famous COLLE crystal works, merging the two companies under one brand with one production system.
COLLEVILCA is currently the Italian company that holds and transmits the great artisan tradition for crafting crystal, creating its products exclusively in its plant in Colle di Val d’Elsa (Siena, Italy).
Glass and crystal are two materials that are obtained by means of a melting process, that is to say, by heating a mass of special components until it melts and then cooling it so as to obtain a vitreous state.
Not all substances, cooled from their liquid state, can become glass. In fact, most elements and compounds, after melting and cooling, return to their original state (e.g., metals).
The commonest substances that can exist in the vitreous state are: silica, boric oxide and phosphoric oxide. These substances are called in fact VITRIFIES and they have the lion’s share of the composition necessary to obtain glass.
Glass formed, for example, just from silica would be difficult to make. As already mentioned, the material must be melted and, given that the melting point of silica is 1700 C°, it would be necessary to have special furnaces to reach such an elevated temperature; furthermore, this kind of glass would be very difficult to work.
When manufacturing normal glass, other materials are therefore added to the silica, especially compounds of sodium and potassium, to lower its melting point. These substances are called FLUXING AGENTS.
Glass made from silica, sodium and potassium is very unstable as it is soluble in water and can therefore be easily attacked by atmospheric agents (e.g. common glass).
Therefore, in order to make CRYSTAL, other substances, called STABILIZERS, must be added to the composition of common glass.
Basic raw materials:
Extra raw materials:
FIRERS: These are the raw materials whose oxides can produce glass on their own.
Silicon dioxide, Silica – (Sand and quartzite)
Boric oxidea – (Boric acid, Borax)
Phosphoric oxide – (Calcium phosphate, Sodium phosphate, animal and vegetable ashes)
FLUXING AGENTS: These are used to lower the melting point of the silica.
Sodium oxide – (Sodium chloride or salt, Sodium sulphate, Sodium carbonate)
Ossido di Potassio – (Potassium carbonate or Potash)
STABILIZERS: These make glass chemically stable, in other words, they stop it from dissolving in the presence of atmospheric agents:
Calcium oxide – (Calcium carbonate, Dolomite)
Magnesium oxide – (Magnesite, Dolomite)
Aluminium oxide – (Aluminium hydroxide, Kaolin)
Barium oxide – (Barium carbonate, Barium nitrate)
Lead oxide – (Minium, litharge)
Zinc oxide – (White zinc, Zinc carbonate)
REFINING AGENTS: These are used to homogenize the melted material to make it purer
White arsenic – (Antimony)
The main difference between Glass and Crystal lies in the presence of lead oxide. This oxide gives glass certain characteristics that make it particularly interesting. PbO, in fact, increases the density of glass and consequently greatly increases its refraction index. This kind of glass thus approaches the optical properties of diamonds: the light that touches it is refracted much more than normal glass thus giving it that particular brilliance typical of lead crystal.
The greater the content of lead oxide, the greater is this effect. Only glass that contains at least 24% lead oxide can be legally called CRYSTAL or Crystal Glass. A higher content of lead oxide, however, would give a yellowish color to the glass. Only with the close collaboration between specialized chemists and master glassblowers can the composition turn into a clear, transparent, brilliant and stable material, worthy of being called CRYSTAL.
Public opinion is extremely aware of issues regarding the toxicity of articles produced for alimentary use and has raised questions concerning the presence of certain substances in crystal that are potentially harmful to health.
The substance present in crystal which has most interested researchers in recent years is lead.
Recent and sophisticated scientific research carried out on behalf of ColleVilca, aimed at highlighting the aesthetic characteristics of the product as well as the stability of its elements, have enabled the company to alter its crystal composition so as to comply with EEC law, as proved by the lead release indexes of ColleVilca crystal that is regularly tested and indicated in the guarantee attached to each article placed on sale.
The aesthetic result is further highlighted by scientific testing of refraction, hydrolytic classification and percentage of lead content.
The COLLEVILCA crystal is among the best crystal available on the market.
Tests performed demonstrate that it is the most transparent and one of the very best for its brilliance.
It is a unique combination of Sonority, Brilliance, Transparency and Dishwasher Resistance.
Its Brilliance is characterized by a high Refraction Index nD >1.56 (measurement made according to regulations in the visible field at 589.3 nm).
Its Transparency is matchless if one thinks that a glass thickness of 30 mm transmits light achieving a value of L >95.5, unique in its kind (L air = 100), determined according to CIE 1976 L*a*b*.
Unique Dishwasher Resistance for lead crystal compliant to EN-12875 standards, guaranteeing a minimum of 500 wash cycles, which in normal practice would correspond to an unlimited use of the article over time!
Its residual color is close to absolute white (air), also determined on a thickness of 30 mm. In fact, the color factor (F) is remarkably low (0.013).
Last but not least, its Sonority is achieved thanks to the particular lead content, which produces a long, unmistakable and persistent sound frequency, which will never be equalled by lead-free glass or crystal.
A balanced composition that allows full compliance with the regulations presently in effect. (69-493 CEE)
These results are truly striking and the values would even improve if they were determined at lower thicknesses!!
But the purpose of presenting values at higher thicknesses is that of demonstrating that ColleVilca not only produces goblets, but also other articles, and that quality is guaranteed for the entire product range and for all thicknesses.