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Sylvia Rose

Fulminating Gold: Blowing It Up in Alchemy

Updated: Sep 27

Fulminating Gold (aurum fulminans) is the first high explosive known, recorded in Western alchemy c. 1585. Sebald Schwaerzer is the first to isolate this compound and comment on its characteristics in his book Chrysopoeia Schwaertzeriana.



Fulminating Gold - highly explosive with vapors of purple
Fulminating Gold - highly explosive with vapors of purple

Fulminating gold is a yellow to orange non-crystalline mix of compounds, primarily gold, ammonia and chlorine. The gold reacts with the chlorine and dissolves (gold(III) chloride). Sensitive to light and shock, fulminating gold can't be defined by a chemical formula.


Gold(III) chloride (AuCl3) is first made independently in1666 by alchemist Robert Boyle (author of The Skeptical Chymist 1661). He creates gold (III) chloride form gold and chlorine gas, involving the reaction of metallic gold and chlorine gas at 180 °C (365 °F).


2 Au + 3 Cl2 → Au2Cl6


This is still the most common method of preparing gold(III) chloride.



Aqueous solution of gold(III) chloride
Aqueous solution of gold(III) chloride

In the alchemical context, "fulminating" refers to its oldest meaning, "explosive." It's derived from Latin fulmen (lightning), from the verb fulgeo, meaning 'I shine.' Despite its name, the material does not contain fulminate ions. Upon combustion, it produces purple vapor.


If exploding gold weren't enough, the purple vapor brings an arcane mystique to the process. Purple and gold are both colors of royalty, status and prosperity, and who doesn't want a little of that? But no one is even sure what to do with it all.



purple vapor
purple vapor

Schwaerzer's process requires dissolving a sample of gold in aqua regia. Aqua regia, a mixture of nitric and hydrochloric acids, is strong enough to dissolve gold and platinum, which even the divine water, sulfuric acid, can't break down.


One aim of alchemists, often overshadowed by lead-to-gold cliche, is creation of a universal solvent. When the gold is dissolved, Schwaerzer adds ammonium chloride or sal ammoniac to the saturated solution.



Salammoniac, Belgium
Salammoniac, Belgium

Schwaerzer then precipitates the solution through lead spheres. When the precipitate forms he dries it over oil of tartar (cream of tartar, potassium bitartrate).


Many alchemists of the 16th and 17th centuries are intrigued the novelty of an explosive gold compound, and this throws a wrench into the works of Renaissance gold fever. It seems some alchemists are less interested in making gold than making gold explode.



woman with hair flying
I told you to leave the chemistry set at home

The volatility of the compound causes serious injuries when glass or ceramic vessels explode. Many alchemists of the era are injured when it detonates. It's not until Johann Glauber (1604 - 1670) makes the scene that fulminating gold starts to have a use beyond risky entertainment.


Glauber captures the purple fumes after detonation to plate objects in gold. Later on, it's applied in photography due to its light-sensitive nature. The unusual color of the smoke is caused by diverse gold nanoparticles.



the allure of gold
The allure of gold

By the late 18th century alchemical dressings are falling away and people who practice alchemy now practice chemistry. In Arabic the word كيمياء (kimya') means "chemistry" with al meaning "the". Thus there is no distinction between kimya' and al-kimya'.



Non-Fiction Books:


Fiction Books:

READ: Lora Ley Adventures - Germanic Mythology Fiction Series

READ: Reiker For Hire - Victorian Detective Murder Mysteries





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