Tag Archives: georg gebhard

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