Tag Archives: chemistry

Marshite, Palladium, and Plattnerite

My latest order from Dakota Matrix arrived a couple of weeks ago, consisting of three relatively rare species.  Marshite is my first representative of an applicable copper halide, it’s an iodide with a simple formula of just CuI.  Like many other classic metal halides like Chlorargyrite or Nantokite, this Marshite hails from the Broken Hill Proprietary Mine in New South Wales, Australia.  The specimen seems to be a fragment of gossan matrix with patches of colourless to honey coloured octahedrals of Marshite; also present are yellowish crystals of Miersite, a halide species with a formula of (Ag,Cu)I.

Cu3D.01  Marshite Photo by Dakota Matrix

Cu3D.01 Marshite
Photo by Dakota Matrix

Cu3D.01  Marshite Photo by Dakota Matrix

Cu3D.01 Marshite
Photo by Dakota Matrix

Cu3D.01  Marshite Photo by Dakota Matrix

Cu3D.01 Marshite
Photo by Dakota Matrix

Cu3D.01  Marshite Photo by Dakota Matrix

Cu3D.01 Marshite
Photo by Dakota Matrix

Finding Palladium for sale was a bit of a surprise, but this specimen seems to have been personally collected and owned by William Hyde Wollaston, 1766-1828, and the discoverer of elements palladium and rhodium.  This specimen is attributed as Wollaston’s due to the inclusion his label from 1803.  However, the label is a photocopy of the original, it’s unknown why the original label was not included…  Before Dakota Matrix acquired this specimen, it had been previously owned by Georg Gebhard, 1945-, German chemist and mineral collector for whom the mineral Gebhardite is named.  I inquired of Dakota Matrix why the original Wollaston label is not present, they are attempting to contact Gebhard…  In the meantime I hope it’s not some ploy to falsely authenticate specimens with photocopied labels??  Hmmm…  At any rate this specimen, from Minas Gerais in Brazil,  is a pinch of small silvery grains sealed in a corked vial.  I’m also waiting to see if Dakota Matrix can tell me if the vial is Wollaston’s own.  Of course, there is never really any pure native Palladium found in the wild, it always contains some Platinum, giving a formula of (Pd,Pt).

PdB3/6.01  Palladium Photo by Dakota Matrix

PdB3/6.01 Palladium
Photo by Dakota Matrix

PdB3/6.01  Palladium Photo by Dakota Matrix

PdB3/6.01 Palladium
Photo by Dakota Matrix

Photocopy of Wollaston's original label for PdB3/6.01  Palladium Photo by Dakota Matrix

Photocopy of Wollaston’s original label for PdB3/6.01 Palladium
Photo by Dakota Matrix

The lead oxide Plattnerite (PbO2) is one of those species that should be more commonly available than it is.  One can usually find Plattnerite pictures in somewhat expansive coffee table book about minerals, Pough’s Field Guide to Rocks and Minerals details the species…  But I had acquired other examples of other lead oxides, Minium and Scrutinyite, long before I found this specimen.  This specimen is from the famous Ojuela mine in Mapimi, Durango, Mexico and exhibits the standard acicular habit Plattnerite is known for.

Pb4.3/10.01  Plattnerite Photo by Dakota Matrix

Pb4.3/10.01 Plattnerite
Photo by Dakota Matrix

Pb4.3/10.01  Plattnerite Photo by Dakota Matrix

Pb4.3/10.01 Plattnerite
Photo by Dakota Matrix

Pb4.3/10.01  Plattnerite Photo by Dakota Matrix

Pb4.3/10.01 Plattnerite
Photo by Dakota Matrix

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Elements of Childhood

When I around ten or twelve years old I was interested in astronomy, anatomy, dinosaurs, insects, and Lego.  So when I learned that all matter is composed of molecules which are composed of atoms, all of which are listed on something called The Periodic Table, I was instantly fascinated.  All those  elements laid out in that block grid like some alphanumeric skyline…  Some of the elements were familiar but many sounded strange and exotic, like Gallium, Osmium, or Technetium…  For myself, and I’m sure for anyone who became an Element Collector, the periodic table embodied a kind of completeness – a masterlist of the ingredients for everything there is, was, and likely will ever be.

So among my collections of fossils, mounted insects, and Lego, it seemed perfectly natural to start up an element collection.  I didn’t get very far.  In the 1980s, before the internet and  sites like Metallium or Element  Displays  obtaining pure samples of elements would have been more difficult.  While I’m sure there were, at the time, various science supply stores and the like to aid in furnishing an aspiring element collector, any purchases would have likely been carried out through some mail order catalogue, and often sight unseen.  Hardly the convenience and immediacy of today’s on-line ordering of goods.  But this never occurred to me, as a 12 year old boy with a very limited weekly allowance.  Indeed, I set about obtaining various materials and objects known to be made of or contain, at least to some degree, the element I sought.  Naturally I was most interested in obtaining the purest form of the element, but I quickly realized that this was not always possible.  I actively collected for a couple of years, during grades 6 and 7 at school…

From the depths of my memory this is what I recall of my first and only element collection:

Hydrogen
I believe I had a small jar/vial of the gas obtained from a simple chemical experiment done in the kitchen, although I can’t remember what the reactive ingredients were…

Helium
A helium filled balloon was the obvious choice, but of course the gas gradually escaped leaving me with an empty limp balloon skin.

Beryllium
A piece of Beryl

Carbon
A piece of carbon paper

Nitrogen
My Dad helped me obtain this; first we fixed a small candle to the inside of a jar lid.  The candle was lit and the lid was sealed onto the jar, held upside-down, with the candle still burning.  After a few seconds the flame went out and then the jar, still upside-down, was opened.  After a few seconds the lid was put back on the jar.  The idea was that the flame would convert the oxygen inside the jar to carbon dioxide which would then fall out of the opened upside-down jar.  The remaining gas left in the sealed jar would presumably be (mostly) nitrogen.

Fluorine
An octahedral cleavage of Fluorite

Sodium
Table salt

Magnesium
A strip of pure magnesium pilfered from science class

Aluminium
A piece of aluminium foil

Silicon
I recall having a disc of silicon, it was very thin, slightly smaller than a CD in diameter, and mostly circular except for a couple inches of a straight edge.  It was my understanding that it was an example of stock material used in the manufacture of computer processor chips.  This example was really brittle, and it didn’t take long before it was reduced to a number of splinters.

Phosphorous
A book of matches

Sulphur
As a powder in a reused tic-tac container

Calcium
A seashell

Chromium
I can’t remember exactly what the item was, but it had chrome plating

Iron
Some iron filings, can’t remember where I got them; I believe a ball bearing was also included

Cobalt
This was a vial of cobalt chloride (most likely hexahydrate) from my junior chemistry set.

Nickel
At first I used a nickel coin.  Later I acquired a cluster of those man-made nickel crystals that some unscrupulous mineral dealers try to pass off as “natural.”

Copper
A penny

Zinc
A zinc (plated) screw/nut

Silver
A tarnished silverware fork that bore the chew-marks of having been caught in the garburator

Cadmium
I have a feeling that I had a small exhausted nickel-cadmium battery for this one…

Tin
I can’t recall the exact item I had for this element, other than it was some small metal container as a “tin.”  In retrospect, it’s most likely it wasn’t tin at all.

Tungsten
Light bulb

Gold
The backing of a gold earring

Mercury
I stole a thermometer from my science class, broke it open, and kept the liberated mercury in a sealed jar that once held baby food

Lead
Some of the excess trim/flashing from those miniature Dungeons & Dragons figures sculpted of lead

The entire collection resided inside a bureau, on top of a large chemistry book that was left open to the pages showing the periodic table, every example I had placed on the appropriate square.  After a couple years the collection fell into gradual disarray as things do when you’re young…  I moved on to collecting other things like comic books and World War One medals/memorabilia.  As for my element collection, most of the samples got thrown out – don’t know what happened to some of the more toxic items like the mercury..(!)

I now have a young daughter who is quite curious about the natural world around her.  Should she be interested enough in chemistry or the elements to build a collection of her own then I look forward to helping her, I think it will be easier to do this time around..!