- Goldstone (gemstone)
Goldstone is a type of
glass made withcopper orcopper salt s in the presence of a reducing flame. Under normaloxidative conditions,copper ion s meld into thesilica to produce transparent bluish-green glass; when the reduced goldstone melt cools, the copper remains inatomic isolation andprecipitate s into smallcrystalline clusters. The finished product can take a smooth polish and becarve d intobead s,figurine s, or other artifacts suitable forsemiprecious stone, and in fact goldstone is often mistaken or misrepresented as a natural material.The most common form of goldstone gives the illusion of being reddish-brown, although in fact that color comes from the copper crystals and the glass itself is colorless. Some goldstone variants have an intensely-colored glass matrix—usually blue or violet, more rarely green—and a more silvery appearance to the
suspended crystal s, whose color may be partially masked by the glass or which may be based on different metals than copper (perhapscobalt ,manganese , orchromium ).The
manufacturing process for goldstone was discovered inseventeenth-century Venice by theMiotti family, which was granted an exclusive license by the Doge. Persistentfolklore attributes the discovery and secret of goldstone to an unnamed Italianmonastic order , giving rise to the alternate name "monk's gold" or "monkstone". Another name, "stellaria", is based on the starry internal reflections.Curiously, goldstone is one of the few cases where a synthetic
simulant provided theeponym for the similar natural stone. The original Italian name for goldstone is "avventurina" or some similar word or phrase indicating its accidental discovery, hence themineral name "aventurine " for forms offeldspar orquartz withmica inclusions that give a similar glittering appearance. Yet another name for goldstone is "aventurine glass", but this should be discouraged to avoid confusion with the minerals.External links
* [http://www.dvpaperweights.org/newsletters/murano_pt1.html] Earliest documentation cited as 1626.
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