The Microscope - Volume 61, Fourth Quarter 2013

IN THIS ISSUE:

On the cover: A crossed polarized light image of an amphibole-talc schist from the Talcville mine. See Compositional Analysis and Morphological Relationships of Amphiboles, Talc and Other Minerals Found in the Talc Deposits from the Gouverneur Mining District, New York (Part 1 of 2), page 147. (Photo courtesy of Brittani D. McNamee and Mickey E. Gunter)

Editorial | Notice: This Microscope Preparation Is Under Video Surveillance

Gary J. Laughlin
The Microscope 61 (4), p ii
Excerpt: Video cameras are seemingly everywhere. Chances are you have already been recorded dozens of times this week, while leaving your home, getting into the car, train or bus, while driving, bicycling or walking to work, and, of course, while shopping. Others are recording us — all the time. But what about our own observations? Are we recording, too? Is there a camera attached to your microscope? Chances are there is. Does it record video and audio, and is it recording every time you are using it? Probably not, but this technology is here, relatively inexpensive and readily available.

Compositional Analysis and Morphological Relationships of Amphiboles, Talc and Other Minerals Found in the Talc Deposits from the Gouverneur Mining District, New York (Part 1 of 2)

Brittani D. McNamee and Mickey E. Gunter
The Microscope 61 (4), pp 147 – 161
Abstract: The authors characterized the chemical composition and morphology of minerals in rock samples and processed products from two former talc mines owned by the R.T. Vanderbilt Company (RTV) in the Gouverneur Mining District in New York State. The main mineral phases within these samples are tremolite, anthophyllite and talc with serpentine, quartz, calcite, and diopside. Bulk analyses of the samples were performed by powder X-ray diffraction (XRD) for structural phases and by X-ray fluorescence (XRF) for bulk chemical composition. Precise compositional data of individual grains were collected by wavelength dispersive spectroscopy (WDS) using an electron microprobe. Mineral formulas were calculated from the resulting weight percent oxides. The morphology of the different mineral phases was observed with backscatter electron (BSE) images and polarized light microscopy (PLM).

All of the mineral phases analyzed have near end-member compositions. The compositions and morphology of the minerals do not vary significantly between the two mines. Tremolite occurs in the samples mainly as unaltered, blocky crystals. Anthophyllite mainly occurs with an acicular texture and a series of fractures perpendicular to the long axis of the crystal. Talc occurs both as platy crystals and as fine-grained asbestiform particles as alteration products of primarily anthophyllite, which occurs in a non-asbestiform habit.

Critical Focus | Brainstorm: New Insights on Human Intelligence

Brian J. Ford
The Microscope 61 (4), pp 163 – 173
Excerpt: Today’s well-funded research into the human mind is founded more on myth rather than a curiosity for exploring what goes on inside the brain’s cells.

Microscopical Study of Sawn Art Glass

Louis Copper
The Microscope 61 (4), pp 175 – 181
Abstract: Fusible art glass that has been cut on a diamond saw will show unsightly evidence of the cuts when it is fused. Visible trails called “veils” appear in the melted material corresponding to the the sawn edges, or “kerf, “ made by the saw blade. This can ruin an otherwise beautiful art work and create limitations for artists in the recycling and maximum use of their raw material. A microscopical study was done to examine the veils generated in this manner. The veils are streams of tiny bubbles that form as the cut edges melted into the body of the work. Various actions were investigated that artists might take to reduce or eliminate the problem. Boiling the diamond-cut glass scraps was found to greatly reduce the number of bubbles formed and greatly improve the appearance. The mechanism for the change in the glass is discussed.

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