There is absolutely no difference between what was often called ‘goldstone’ with the glass which is actually mostly called ‘aventurine’.  Before a German scientist discovered the flecks inside the glass were made of a type of copper, it was assumed that the flecks were of gold, hence the name ‘goldstone’.

All through the 1800’s glass makers in Bohemia were striving to produce unusual, unique and beautiful glass.  Goldstone, or more correctly,  Aventurine produced the most challengers for these determined glass artisans.
The first record of this glass was associated with the Muranese and Venetian glass experts.  There is documentary proof that they had been creating this glass since the 1600’s.

 

The very first mention of this type of glass is seen in 1644 by Giovanni Darduin.  He had written down glass recipes handed to him by his father and other unknown glass artisans.  His aim to was improve upon the recipes and he was the first recorded maker to voice his annoyance at how unpredictable this glass was in manufacture.

The name for this unpredictable glass was decided upon by this gentleman   “…the maker can never be sure to succeed with this glass and thus it is justified to call it (a)venturine.”  “Aventura” means to take a risk or a chance and ‘avventurarsi’ means literally to take a risk and what is obtained is gained by luck rather than any specific knowledge.

There were many other Muranese glass makers who attempted to recreate his formula but the first recipes for Aventurine stayed within the Miotti family who kept their recipes secret until the end of the 1700’s.
At the time Bohemian coloured glass and English cut lead crystal became fashionable (around 1833), Aventurine and other Venetian/Muranese glass took a back seat and were quite unpopular.  The previously mighty influence of these glass makers declined dramatically.

There was a dramatic turnaround which was caused mostly by the exhibition in Vienna in 1845.  Muranese glass (and in particular Aventurine) made an amazing and instant comeback.
Most of the international visitors to the exhibition had come to scrutinize Bohemian glass manufacture in the hope of equalling their success.  They were distracted by the Muranese accomplishments, including Aventurine. The revival in Muranese glass products had started much earlier on the island of Murano more than 25 years earlier.  Medals were awarded to the Muranese in 1825 and 1826 for the production of huge quantities of Aventurine which was exported mostly to America and the Pacific Islands.  Most of the Aventurine produced was used in small quantities in beautiful jewellery.

Records tell us that the first non-Venetian to own a patent for Aventurine glass was issued in 1835 was Joseph Jackel from Neudorf, Bohemia.  It was in 1842 when the German chemist Herr Wohler was the very first scientist to analyse this type of glass.  He understood that the glittering appearance within the glass are in fact tiny pieces of metallic copper, rather than gold.  After the Viennese exhibition in 1845 the French also tried to exploit this suddenly popular glass – they evidently did not succeed as records show them visiting Venice repeatedly to acquire this highly sought after glass.  About the same time European glass makers tried to perfect Aventurine the Muranese discovered that this glass could be reheated and mixed together with other glass.  When re-heated the glittering copper disappears.    There are many other mercurial results when using copper – including a deep transparent red used in many churches.

In the early 1850’s an intense attempt to unravel the mysteries of this glass was undertaken by Herr Pettenkofer in Munich.  These attempts ended c1875 with the definitive discoveries of glass scientist Ebell in Germany.
Despite all this exploration, Northern Europeans still had difficulty in producing goldstone to rival that of the Muranese.  More surprises were in store for those experimenting with copper as an addition to glass.  It was discovered that when cooled quickly the glass turned completely colourless.   But luck could swing the other way and the glassmaker could end up with a batch of very dull dirty brick colour glass which was good for nothing.

The definitive discovery of the precise composition came in the 1870’s when Paul Ebell absolutely proved (what Wohler had assumed in 1842)  that the colour of aventurine is due to crystals of what is known as ‘elementary copper’ rather than crystals of copper oxide. Despite all this new found knowledge, the Muranese still produce the most beautiful and best quality Aventurine glass available.  It is to be admired that despite all the modern scientific experiments, their ancient knowledge remains superior.

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