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What color is gold in nano-state?


#1

Is gold in a nano-state really red? What about other precious
metals? Does this kind of nano colour change effect electro-plating
on dishware etc?


#2

Peter,

Gold nanoparticles seen in suspension may have all kinds of colors.
Gold nanoparticles dried from suspension onto a surface can look
exactly like… gold… if the layer is dense enough and if the
substrate surface is very smooth.

If the substrate surface is NOT smooth, the dried particle layer can
even look black! Gold nanoparticles though, come with myriad coating
types, depending on their intended application, so you would need to
check with the source of the nanoparticle suspension.

This info is from Nic, the Fourth Axis staff nanoscientist.

Mark B
Fourth Axis


#3

Hi Peter,

A friend of mine does work with nano-scale colloidal gold solutions.
Yeah, they’re pink. I have no idea about the dilution, but the ones I
saw were purplish-pink. They may be red at higher concentrations, but
I’d think more purple-ish.

I can’t imagine what use these sort of solutions would be for either
plating or dishware.

FWIW,
Brian Meek.


#4

The influence of colour in nanoparticles is dependent on particle
size, so yes, at some point gold can be red, as it can be yellow,
blue or green etc.

Major strides are being made in cleaning up enviromentally
unfriendly plating processes through the introduction of nano plating
technologies. Therefore, I would assume, that by controlling the
particle size through the synthesizing of material at the nano level,
you could I guess control colour for plating.

One hell of a question, because now I’m wondering about the
application of electroforming gold items of different colours at the
nano level. Don’t want another project, but if John Donivan or James
Binnion get a patent on it, Pete and I want a cut :slight_smile:

Best Regards.
Neil George


#5

There is a current article in Science News

http://tinyurl.com/yffthqd

“Better Living Through Plasmonics” by Jenny Lauren Lee This article
explains what is happening at the nano scale. Here is a quote:

"The genie in the bottle Medieval plasmonics Plasmonic effects
create some of the brilliant colors in stained glass, such as
those at La Sainte Chapelle in Paris. Bryan Busovicki /
Shutterstock Surface plasmons are effectively ripples in a pond
of freely floating electrons on the surface of a metal that has
a lot of unbound electrons to spare. Gold and silver work
particularly well: Shine a beam of light onto a nanosized plate
of gold, for example, and free electrons will carry that light
along. Though the wave moves across the plate, the electrons
themselves do not travel far, similar to the way baseball fans
can do "The Wave" without moving from their seats. 

Surface plasmons may sound exotic, but they are present in a
number of familiar places. Many medieval stained glass windows
get their brilliant red and blue hues from nanoparticles of gold
and silver suspended in the glass. Light passing through the
glass sets off an oscillating plasmon wave that rings the metal
bits like bells and scatters the light. Different scattering
patterns appear depending on the angle of the sunlight. a single
piece of glass can change from red to green as the sun sets." 

Wow! I am sorry, what were we talking about? I think my brain just
fried.

Bill


#6
Major strides are being made in cleaning up enviromentally
unfriendly plating processes through the introduction of nano
plating technologies. Therefore, I would assume, that by
controlling the particle size through the synthesizing of material
at the nano level, you could I guess control colour for plating. 

Is this the same as “allotropes” of gold?


#7
Therefore, I would assume, that by controlling the particle size
through the synthesizing of material at the nano level, you could I
guess control colour for plating. 

Am I missing something or does this seem a tad ridiculous? The gold
might look different colours at different particle sizes at the nano
level, but as soon as you build up the gold when plating, you no
longer have nanoparticles and therefore it will be gold coloured. Or
perhaps I misunderstood what you were trying to say.

Helen
UK


#8
Is this the same as "allotropes" of gold? 

There is an allotropic gold capable of forming crystals and another
that is considered to be an amorphous pulverulent gold that is brown
or black in colour, but that’s all I know.

How it would relate to nanoparticles in a pure form, I would say it
does not excist as an allotrope, but having said that, I don’t know if
the addition of an anion into the mix, would qualify as another
element that essentially changes the physical properties of the gold,
because an anion can be absorbed if I recall correctly.

Silver on the other hand has some interesting ones where one
resembles gold in colour and lustre.

Are you in search of the Philosopher’s Stone?

Best regards.
Neil George


#9
The gold might look different colours at different particle sizes
at the nano level, but as soon as you build up the gold when
plating, you no longer have nanoparticles and therefore it will be
gold coloured. Or perhaps I misunderstood what you were trying to
say 

Yes that would be correct in traditional plating procedures.

However you left out where I mentioned Nano Plating which is a spray
application and is baked on. Dishware is normally baked, rather than
Electro-Plated because of the heat involved. Maybe I should have been
more specific, but then again, Peter did specifically mention
dishware, and yet you managed to get us both back on track and stick
to jewellery :slight_smile:

Take a look at the link below, and before you start reading, just
scroll down to page 110 where it shows a beautiful Red Gold
Nanoparticle Gold paint. What this provides is the essence that colour
can be controlled at the nano level.

http://tinyurl.com/yehkcos

Think outside the box, but more importantly, think outside of
jewellery.

Best regards.
Neil George


#10

Thank you for all of this Neil.

You did say philosopher’s stone and not stoned philosopher. When I
am not prospecting I collect gold plated china from second hand
stores. I have an English piece which says 22 carat gold and it is
the yellow I see in nature. I have a German piece which says 24 carat
and it is a reddish yellow.

I have many stone samples of what I also call "patinas" 

In ontology they are what they are: thin layers of mineral matter on
a rock face… As for etiology my guess is that they are fracture
faces on which cold and warmer waters have deposited mineral cystals
from plutonic sources. Epistemologically I would say both plutonist
and neptunist forces at work. They are usually metallic but
sometimes vitreous. Assaying for the former is difficult but do-able
while the latter still escapes me. Even if I had the best jeweller in
the world out there in the field I doubt we could figure it out. And
in the lab? Who knows?

So let us say emerald dust is ground up from shaking of the bedrock
(volcanoes, earthquakes etc) and it moves through cracks, fissures,
conduits, faults… call it what you will. It then coats a rock
face. It could be coated by ionic splits from complex mineral
molecules or from charged non-ionic nanoparticles (plasmas?) or from
larger non-charged suspended materials.

The colour range is extended if allotropes are added to all this.

These patinas could be valuable gems in themselves. Suppose I do
have a sample of emerald patina here. My guess is that it would
fetch a good price in the jewelry market. 

Maybe we will find that philosopher’s stone among the moon stones.
Gotta wonder how well the Canada Arm robots (reduced in size) would
fare as tele-robotic miners.


#11
Dishware is normally baked, rather than Electro-Plated because of
the heat involved. 

Yes indeed, but I didn’t realise that it could give anything other
than a gold colour. Thanks for enlightening me.

Think outside the box, but more importantly, think outside of
jewellery. 

I do indeed think outside of jewellery, both in terms of jewellery
technologies which could be used in other industries, and other
technologies which might apply to jewellery. My brain is never idle.

Helen
UK


#12
Take a look at the link below, and before you start reading, just
scroll down to page 110 where it shows a beautiful Red Gold
Nanoparticle Gold paint. What this provides is the essence that
colour can be controlled at the nano level. 

Seeing that reminded me of something I had forgotten from school.
Glass is often colored by the addition of metals and metal oxides.
Those beautiful blue glass bottles referred to as cobalt blue,
actually have cobalt dissolved in them. Gold, oddly enough, doesn’t
dissolve in glass, but makes a colloidal dispersion (lots of
particles floating in it) that is a lovely ruby red color. In a way
it’s glass suspension of nanoparticles that is red just like the
painted model car.

Some old chem labs still have gold glass flasks and beakers in them,
and the younger researchers never know what they are or how
expensive they are to produce.

Jason


#13
I do indeed think outside of jewellery, both in terms of jewellery
technologies which could be used in other industries, and other
technologies which might apply to jewellery. My brain is never
idle. 

Any new and interesting technologies tickling your fancy right now?

Best Regards.
Neil George