Aventurine is a glass in which copper particles are suspended to give it a shimmer. Two different Italian words have been invoked to explain its name. Avventízio is equivalent to "adventitious" (the glass is supposed to have been discovered by accident). Avventuràto means "fortunate," as the discoverer was lucky. Both suggest that it was first produced by chance.

The base glass is usually brown, giving it another name, "goldstone." Other colors (green, blue, etc.) are less often used; they have inclusions other than copper. The term "goldstone" is never applied to the stone aventurines.

In any case, the lucky inventor, Vincenzo Miotti, was granted the exclusive right to make it by the Doge of Venice in 1677. The secret was passed on through the family until they stopped making glass in 1731. Other glassmakers tried to imitate it, especially the Bertolini brothers in the 18^th century, but their product was inferior.

In 1811 a Miotti widow revealed the family secret to another glassmaker. By mid 19^th century several formulae for aventurine were published and various improvements were made to it. In time, it came to be made in several countries, though the Venetian remains the best and most widely used. It is said that there was even a patent for it in the USA, but I have not been able to verify this.

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