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Pure gold source
A high-purity gold source provides the elemental metal from which fine particles are formed.
Nanoscience history · 1857
Michael Faraday and the birth of colloidal gold
Long before the words nanoparticles or nanotechnology existed, Faraday prepared and studied one of the most important gold-based materials in scientific history: ruby-red colloidal gold.
In 1857, Michael Faraday investigated what he called “divided gold” — tiny particles of elemental gold suspended in liquid. Today those preparations are recognised as early gold nanoparticles and among the first metallic gold colloids carefully documented in the scientific record.
The Royal Institution notes that Faraday’s gold colloids were made in the basement laboratory at the Ri and remain among the earliest examples of metallic gold colloids, produced more than a century and a half ago. Remarkably, some samples are still optically active: they still interact with light in a way that reveals suspended particles within the liquid.
Faraday fact
Faraday noticed a ruby-coloured fluid while working with very thin gold films. When light was shone through the liquid, suspended particles scattered the beam — what later became known as the Faraday–Tyndall effect.
Who was Michael Faraday?
A mind that shaped modern science
Michael Faraday was one of the most influential scientists of the nineteenth century. His work helped shape modern electricity, electromagnetism, electrochemistry and experimental physics.
He is often remembered for electromagnetic induction, motors and generators. Yet his work with gold colloids is equally fascinating because it places him at the very beginning of what we now call nanoscience.
At the time, Faraday could not see nanoparticles directly — electron microscopes did not exist. Through observation, light experiments and careful reasoning, he realised that the ruby liquid contained particles of gold too small for the instruments of his age to resolve.
Definition
What is colloidal gold?
Colloidal gold is a suspension of tiny particles of elemental gold dispersed throughout a liquid — typically purified water. Unlike dissolved gold salts, a true colloidal gold contains actual particles of the metal itself.
When gold is reduced to the nanoscale, it behaves differently from bulk metallic gold. A gold bar appears yellow because it reflects light from a large metallic surface. Gold nanoparticles, by contrast, interact with light through their surface electrons, creating colours that range from ruby red to purple depending on particle size, shape and distribution.
That is the quiet physics behind the colour in the glass — not a dye poured into the bottle. Read our short guide to what colloidal gold is →
From metal to suspension
How gold becomes colloidal gold
Modern production is far more controlled than nineteenth-century chemistry, but the principle remains elegant: pure gold is transformed into microscopic particles and held throughout purified water.
Controlled energy
Electrical or chemical processes separate tiny particles from the source under measured conditions.
Particles form
Gold particles form at the nanoscale — where optical behaviour becomes highly distinctive.
Ruby suspension
When light meets the particles, the liquid can display the famous ruby-red appearance.
At Auria we work in this lineage of careful craft: elemental gold, purified water, formulated at 40 PPM, and a glass vessel — see how we make the bottle.
Optics
Why is colloidal gold ruby red?
The colour is not a dye, flavouring or pigment. It is physics at the nanoscale — light meeting ultra-fine gold.
Surface plasmon resonance
When light meets gold nanoparticles, electrons on the particle surface oscillate together. That collective motion is known as surface plasmon resonance.
The particles absorb and scatter selected wavelengths, leaving the liquid with its characteristic ruby appearance. Change size, shape or aggregation, and the colour response can shift — which is why laboratory gold colloids are so closely studied in optics.
Science callout
Surface plasmon resonance is one reason gold nanoparticles appear in modern biosensors, optical research and materials science. Colour and light response can change with particle size, shape, surrounding molecules and aggregation state.
Scale
Why particle size changes everything
At the nanoscale, materials can show behaviour that does not appear in larger forms of the same substance. That is one reason gold nanoparticles became so important in modern science.
Human hair (width)
~80,000 nm
Red blood cell
~7,000 nm
Typical virus
~100 nm
Gold nanoparticle
~5–100 nm
Nanoparticle fact
The same metal can behave differently depending on scale. Bulk gold appears yellow and metallic. Nanoscale gold can appear ruby red because surface electrons interact with light differently.
Light & observation
Faraday, light and the Faraday–Tyndall effect
Faraday did not have modern imaging technology, but he did have extraordinary experimental skill. When he shone light through his gold colloids, he observed a visible cone of light inside the liquid.
The Royal Institution records his notebook observation that “the cone was well defined in the fluid by the illuminated particles.” That is the Faraday–Tyndall effect: light scattering from particles suspended in a liquid.
The observation helped Faraday understand that the ruby fluid contained tiny suspended particles — even though those particles were too small to see directly.
Modern research
How gold nanoparticles appear in science today
Gold nanoparticles are widely studied in modern research because size, surface chemistry and optical properties can be carefully engineered. That interest does not mean every wellness claim about colloidal gold is proven — it explains why laboratories take the material seriously.
Cellular models
Researchers explore how engineered particles may interact with membranes, proteins and signalling systems in controlled experiments.
Surface chemistry
Particle surfaces can be modified for biosensor design and molecular interaction studies.
Optical response
Strong interaction with visible light makes gold nanoparticles valuable in detection and imaging research.
Research caution
Scientific interest is not the same as proven health outcomes. Effects depend on formulation, exposure route and study design.
Important distinction
Neuroscience and nanomedicine literature sometimes explore engineered gold nanoparticles in highly specialised experimental settings. That is very different from claiming any commercial colloidal gold product treats neurological conditions or automatically crosses the blood–brain barrier. The responsible position: the research field is technical, developing, and not a substitute for medical advice.
Literature context
Areas of study — not product claims
Many papers investigate gold nanoparticles in experimental models related to sensing, imaging, surface chemistry and cellular pathways. The most responsible reading separates laboratory research from consumer wellness claims.
Gold nanoparticles may show interesting behaviour in experimental systems, but clinical relevance depends on dose, particle size, coating, route of exposure and safety data. Auria is a food supplement with a short formula — elemental gold and purified water, formulated at 40 PPM. We do not overclaim. We point to craft, clarity and history.
Then to now
The journey from Faraday to modern materials
Faraday’s ruby-red liquid became a bridge between Victorian chemistry and twenty-first-century materials science.
1857
Bakerian Lecture
Faraday publishes experimental relations of gold and other metals to light — documenting “divided gold” and its optical behaviour.
Late 19th–20th c.
Colloid chemistry grows
Tyndall, Zsigmondy and others deepen the science of fine suspensions; colloidal gold becomes a classic demonstration of nanoscale optics.
Late 20th c.–today
Plasmonics & nanotechnology
Surface plasmon resonance and engineered gold nanoparticles underpin research in biosensing, imaging and advanced materials — always distinct from casual product claims.
Auria
Quiet British craft
One bottle. Elemental gold. Purified water. Formulated at 40 PPM. Faraday-inspired care without theatre.
Legacy
Why Faraday’s original gold colloids still matter
One of the most remarkable details from the Royal Institution collection is that Faraday’s original colloids remain optically active after more than 150 years. Many colloids last months or perhaps a year, making the survival of those samples scientifically unusual.
For Auria, this history matters because it reminds us that colloidal gold is not merely a modern trend. It is rooted in one of the earliest chapters of nanoscience — careful observation, light, and metal reduced to a scale the eye cannot resolve.
Auria · Colloidal Gold
From Faraday’s ruby fluid to a calm daily pour
True colloidal gold at 40 PPM — elemental gold in purified water, glass-bottled in Britain. Short formula. Clear standard.
Questions
Frequently asked
Did Michael Faraday invent colloidal gold?
Faraday did not invent gold nanoparticles in the modern manufacturing sense, but he was one of the first scientists to document and study metallic gold colloids in careful experimental detail.
Why is colloidal gold red?
Colloidal gold can appear ruby red because gold nanoparticles interact with light through surface plasmon resonance — not because a dye is added to the liquid.
What are gold nanoparticles?
Gold nanoparticles are tiny particles of elemental gold measured in nanometres — billionths of a metre. Their optical behaviour differs from bulk gold metal.
Are gold nanoparticles used in science today?
Yes. They are studied across nanotechnology, biosensing, imaging, plasmonics and advanced materials. Laboratory interest should not be confused with product health claims.
Is ruby-red colour natural?
The ruby appearance can arise naturally when gold nanoparticles are correctly formed and dispersed. The colour comes from light interacting with the particles.
Does this mean colloidal gold is a medicine?
No. Auria Colloidal Gold is a food supplement. Historical science and modern research context do not make consumer products into treatments. Always read the label and use as directed.
Sources
References and scientific context
- Royal Institution. “Michael Faraday’s gold colloids.” Collection notes describe these liquids among the first metallic gold colloids, Faraday’s ruby fluid, light-scattering observations, and long-term optical activity. View source
- Faraday, M. “The Bakerian Lecture: Experimental Relations of Gold and Other Metals to Light.” Philosophical Transactions of the Royal Society, 1857.
- Research literature on localised surface plasmon resonance explains how conduction electrons on gold nanoparticle surfaces oscillate with incident light, producing distinctive optical colours.
- Modern materials and sensing literature continues to explore engineered gold nanoparticles for biosensing, imaging and optical applications — distinct from consumer product claims.
