From Root To Crown · A Crystal special
The hidden history of colloidal gold
Gold has a story beyond the vault.
Ancient traditions, ruby glass, Faraday’s flask and the microscope that made particles visible. Follow the long story of gold from treasured metal to colloidal liquid.
The history, in brief
What is the history of colloidal gold?
Gold has been valued in objects, art and traditional preparations for centuries. The story of colloidal gold takes a more specific turn in the nineteenth century, when Michael Faraday investigated tiny particles of gold dispersed in liquid and the colours they produce.
Later, Richard Zsigmondy developed methods to study colloids and received the 1925 Nobel Prize in Chemistry. This is our independent tour through the traditional record, the laboratory, and the story of the bottle today.
Explore the gold ingredient guide or follow silver’s separate history.
Follow the centuries
Colloidal gold history timeline
| Period | In the record | Why it matters |
|---|---|---|
| Antiquity | Gold in vessels, ornaments and traditions | The cultural history of gold is older than the modern colloid. |
| 1600s | Purple of Cassius and ruby glass | Fine gold becomes part of a distinctive colour story. |
| 1856–1857 | Faraday’s investigations into gold and light | A landmark experiment and paper on finely divided gold. |
| 1861 | Thomas Graham names colloids | A name for a developing field of study. |
| Early 1900s | The ultramicroscope | New methods make scattered light from tiny particles observable. |
| 1925 | Zsigmondy awarded the Nobel Prize | Colloid chemistry is recognised for its experimental methods. |
| Today | Gold research and independent workshops | Gold continues to be explored in many different forms. |
Antiquity · Gold in tradition
Gold before the laboratory
Gold was never only money. It appeared in vessels, jewellery and objects of ceremony, valued for its colour, rarity and resistance to tarnishing. Historical and traditional accounts also describe gold preparations in different cultures.
In Ayurveda, gold is known as Swarna; traditional preparations belong to a specific body of practice and are not automatically the same thing as a modern water-based colloid. The vessels, the traditions and the later laboratory work are connected by the metal, while each chapter has its own context.
The older gold traditions invite curiosity about why people continued to value this element beyond its price. They are part of the record Crystal wants to keep visible.
The thread: The cultural history of gold reaches further back than the modern colloid.
1600s · Gold in glass
Purple of Cassius
Gold can make a remarkable colour when it is divided into exceptionally fine particles. In seventeenth-century glassmaking, gold-based materials became associated with ruby and purple colours. One historical name is Purple of Cassius.
It is a different material from gold dispersed in water, but both belong to the history of small particles and light. Richard Zsigmondy later investigated Purple of Cassius while studying finely divided gold and colloidal materials.
What the glassmakers could see by eye would later become a laboratory question: what is in the colour, and how does the material behave?
The thread: Ruby glass and gold hydrosols are related by their finely divided gold, with different materials and settings.
1856–1857 · Michael Faraday
Ruby water, gold and light
At the Royal Institution, Michael Faraday investigated how gold behaves in very thin films and when it is finely divided. Some preparations formed liquids with a striking ruby colour. His research put gold, particles and light into a new experimental relationship.
His Bakerian Lecture, Experimental Relations of Gold (and Other Metals) to Light, was received in 1856, read in February 1857 and published in the Royal Society’s Philosophical Transactions. The paper is the historical anchor for this chapter.
Faraday was not writing about a Crystal bottle. He was investigating an unusual material and what light could reveal about it. The idea of gold in water, rather than a solid piece of metal, is the connection we find fascinating.
The thread: Faraday’s documented research made finely divided gold and its interaction with light a central part of the story.
From the archive · 1857
Faraday’s paper, in its own words
This is the original heading of Faraday’s paper on gold and light. The paper gives you a way into the historical source itself, with the material, observations and experimental setting on the record.
The heading above is an authentic excerpt from a digitised publication. The atmospheric scenes on this page are modern editorial illustrations.
Explore the original paper
Early 1900s–1925 · Colloid chemistry
Zsigmondy and the ultramicroscope
Richard Zsigmondy studied finely divided gold and the nature of colloidal systems. With Henry Siedentopf, he developed ultramicroscopy methods that made it possible to observe light scattered by particles too small to resolve in an ordinary microscope.
The 1925 Nobel Prize in Chemistry recognised his demonstration of the heterogeneous nature of colloid solutions and the methods he used. His Nobel lecture also describes his investigations of Purple of Cassius and the work of Faraday.
The prize was for the wider study of colloids and experimental methods. Gold was an important part of that story, not the only subject behind the award.
The thread: Zsigmondy’s work turned the behaviour of colloids into something researchers could investigate in new ways.
Traditional preparations · A different shelf
Gold in the older books
Gold has appeared in traditional and historical preparations under different names and in different forms. Early writers discussed aurum potabile, or drinkable gold; later medical records describe still other gold preparations.
One nineteenth-century example was Leslie Keeley’s so-called gold cure for alcohol dependence, offered through residential institutes. His approach combined a claimed gold-containing injection with a programme of support. Contemporary records show a historical claim and a particular treatment programme; they do not establish that this was a water-based colloid or that gold alone accounted for reported outcomes.
Older gold literature also discussed nerves, mood and the joints. These accounts are part of the record, and their preparations and settings matter when reading them alongside a modern bottle.
These sources show what people proposed and recorded in their own time. They do not establish that every preparation was identical, or that an old account proves a particular effect for a modern product. Injections of gold salts, traditional preparations and particles dispersed in water have different compositions and histories.
At Crystal, we think the older record deserves to be accessible and read in context. Questions about who owns a formulation and which research receives attention are also part of our independent perspective on the history of natural materials.
The thread: An older account is most useful when the preparation and its context are named.
The distinction that matters
What is colloidal gold?
Colloidal gold is a dispersion containing very small particles of elemental gold in a liquid. Dissolved gold ions and gold salts are different chemical forms. Depending on how a preparation is made, a liquid can contain different proportions of particles and dissolved material.
Names, colour and concentration describe different things. A familiar word on a label is a starting point; the product’s ingredients and specification give more detail.
Gold · Light · Colour
Why can colloidal gold look ruby?
A block of gold looks golden. When gold is divided into very small particles, its interaction with light changes: certain wavelengths can be absorbed and scattered, giving some dispersions a red, ruby or purple appearance.
Particle size, shape, concentration and aggregation can affect the shade. Colour is part of the visual story, but it cannot on its own establish purity, concentration, particle size or a health effect.
The thread: Colour tells us how a sample interacts with light; it is not a complete specification.
Concentration, plainly
What does 40 PPM mean?
PPM means parts per million. For a dilute water-based liquid, 40 PPM is approximately 40 milligrams of gold per litre. A 500ml bottle at that concentration contains approximately 20 milligrams of gold in total.
PPM describes the amount, not the particle size, stability, purity or composition on its own. A larger PPM number is not automatically a better product.
Crystal’s current listing describes a 500ml, 40 PPM preparation of gold in purified water, in amber glass. Check the product listing and label for its current details.
Explore Crystal colloidal goldThe thread: Concentration and bottle volume answer different questions.
Light and the liquid
What does the Tyndall effect show?
Dispersed particles can scatter light, making the path of a beam visible through a liquid. The Tyndall effect offers a visual illustration of that light scattering.
The beam alone does not identify the particles or measure gold concentration, purity, particle size or safety. It is an observation, not a complete laboratory analysis.
The thread: Light scattering is a clue about a dispersion, not a full product specification.
The film
Watch the gold history film
Questions, answered plainly
Colloidal gold history FAQs
What is colloidal gold?
Colloidal gold is a dispersion containing very small particles of elemental gold in a liquid, often water. Its history includes Faraday’s nineteenth-century research into finely divided gold and light.
When did Faraday investigate colloidal gold?
Faraday’s gold and light paper was received in 1856, read in February 1857 and published in 1857. The sources below link to a digitised copy and the Royal Society archive record.
What is Purple of Cassius?
Purple of Cassius is a historical gold-containing material associated with ruby and purple colour in glass and ceramics. It is part of the history of finely divided gold, but it is not the same preparation as a liquid gold colloid.
Who was Richard Zsigmondy?
Zsigmondy was a chemist who investigated colloids, including finely divided gold. He received the 1925 Nobel Prize in Chemistry for demonstrating the heterogeneous nature of colloid solutions and developing methods to study them.
Is colloidal gold the same as ionic gold?
Colloidal gold refers to dispersed particles. Ionic gold refers to gold present as dissolved ions. Preparations can contain different proportions depending on their chemistry and production.
Why can colloidal gold appear ruby or purple?
Very small gold particles interact with light differently from bulk gold. Size, shape, concentration and aggregation can affect the visible shade. Colour alone does not measure PPM or prove purity.
What does 40 PPM mean?
For a dilute water-based liquid, 40 parts per million is approximately 40 milligrams of gold per litre. A 500ml bottle at that concentration contains approximately 20 milligrams of gold in total.
Does the Tyndall effect prove purity?
No. A visible beam can show light scattering, but it does not identify particles or measure concentration, particle size, purity or safety.
Is historical gold medicine the same as colloidal gold?
Not necessarily. Historical traditions used a range of gold preparations. Gold salts, traditional preparations and modern particle dispersions have different compositions and should be described separately.
How should Crystal’s colloidal gold be stored?
The current product listing advises keeping the bottle closed in a cool, dark place away from direct sunlight. Follow the label on the bottle you have.
Follow the record
Sources and further reading
Read the original work, explore the older traditions and keep the preparation in view. This feature includes historical accounts and Crystal’s independent perspective on the story of gold.
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Michael Faraday, The Bakerian Lecture (1857)
Digitised copy of the original paper and source of the heading shown above. -
Royal Society archive: Faraday’s manuscript
Archive record describing the manuscript and publication. -
Richard Zsigmondy, 1925 Nobel Prize in Chemistry
The Nobel Foundation’s record of the award. -
Richard Zsigmondy, Nobel lecture
His account of work on colloids, Faraday and Purple of Cassius. -
Francis Anthony, aurum potabile (1616)
A historical example of a writer discussing a gold preparation. -
Leslie E. Keeley, The So-Called Gold Treatment of Inebriety (1892)
An original publication record from the nineteenth-century debate about gold and alcohol dependence.
Historical scenes are editorial illustrations unless identified as original archive material.
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