Gem Profile- Goldstone

by Judy Ellis

I've always liked goldstone; it's not really gold, and it's not really a stone, but it sure is pretty! So, if goldstone isn't really gold or stone... what exactly is it? Well, the short version is that goldstone is glass with copper flecks suspended in it, but since I'm not really the short version sort of person... we'll go with a longer explanation.

Goldstone forms by melting silica (sand), copper oxide, borax, and other chemicals.

These reduce copper to its elemental form.

In liquid glass, the vat seals, cutting off all air for an "oxygen reducing atmosphere."

This keeps glass hot enough for metallic flecks to form without melting.

Joan Madouse wrapped this brown goldstone pendant in gold-plated wire.

How Goldstone was Discovered

Goldstone's origins remain sketchy, though legends abound.

Italian monks accidentally spilled copper shavings into molten glass, or tried making gold and created goldstone instead.

Venetian glassmakers credit the Miotti family with inventing the process in the 17th century, holding an exclusive license.

The guarded formula sold in the 19th century after Miotti ceased production, reviving the tradition.

Goldstone's alternate name, aventurine glass, derives from Latin "avventura" (chance); also called sun stone or monk's gold.

Macrocrystalline quartz aventurine named after it due to resemblance.

Rima Kent wrapped blue goldstone pieces in bronze wire for a pendant and earrings set.

Linda Pope made a blue goldstone bead the focal point of a wire-wrapped ring in non-tarnish silver wire.

Avventura and Haematinum

Glass history in ancient Greece and Rome fascinates history buffs.

Roman glassmakers innovated blowing techniques, replacing heavy molded funerary containers and enabling home use like window panes and mosaic tiles.

Pliny the Elder referenced Haematinum, a blood-red (oxblood) glass with suspended copper flecks.

This purpurin process, lost over centuries due to secretive recipes, likely involved copper salts precipitating flakes in cooling glass.

Goldstone mirrors this probably an ancient Roman "avventura" (chance) discovery, rediscovered by the Miotti family.

Jani Mullan beaded a necklace with brown goldstone focal bead; green goldstone beads available on Wi

Colors of Goldstone

Goldstone, with its colored history, comes in various colors as well. The most familiar is the red-brown, but we also have blue, purple, and green.

Sondra Brown-Adams wrapped this brown goldstone cabochon in silver and 14kt gold filled wire.

Purple and blue goldstone use the same process, with cobalt or manganese for silver-like flecks.

Green goldstone employs chromium oxide, yielding light green flecks.

Though not a true stone or gold, goldstone boasts beauty and rich history from the Miotti family and ancient Romans' "avventurina" glass-making.

Carol Roskey wrapped this purple goldstone in sterling silver wire to form a pendant.

Resources & Recommended Reading

Roman Glass Wikipedia

Purpurin Wikipedia

Goldstone: Man-made Aventurine Glass, on MinDat.org

Goldstone Wikipedia

Gem Profile- Goldstone

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