Thread: Calcedony Prep
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Old 01-04-2018, 07:29 PM
Dan Vanantwerp
Posts: n/a
Well, let's ask him...

The above photo of rare earth glasses was lifted from a lecture by Dr. James Shelby, professor emeritus at Alfred University. Here is his response to an email request for clarification on the composition of the Hg labeled glass.
The full lecture can be found here:

"I am very sorry, but there is no mercury in that glass. My handwritten notation is very poor. The g is really an o. The glass contains holmium, not mercury. Although I have personally made a few thousand different glass compositions, Ive never tried to put mercury in a glass (there are several elements I refuse to work with due to toxicity, including mercury, cadmium, tellurium, and selenium probably some others I dont remember right now).

I have read some place about getting some mercury into oxide glasses, but dont have any idea where. I think it was from work very long ago.

Sorry I cant help you on this. I never noticed how bad my lettering was on that slide. Hope no one else was misled.

James Shelby"

Dr. Shelby went on to offer some info about his work on colloidal formation in glass:

"On a separate subject, I did a lot of work on colloids my last few years before retirement. Had a lot of fun working with silver and copper, both with reduction using the tin in the surface of float glass and with reduction using hydrogen. A lot of the work involved diffusing the coloring ion into the glass by exchange with alkali ions in the glass. Since Im not an artist, I never worked with the traditional method of striking to form the colloids.

We also worked with lots of other colloid formation. Arsenic and antimony formed brown glasses in low concentrations (less than 1 wt%). We also made colloids of nickel, cobalt (both magnetic), lead, bismuth, indium. All of those ions result in black glasses.

James Shelby"

Finally, I suggested that he might visit the Craft Web forum to learn about the artists' pursuit of color and glass chemistry. What a surprise response!

"...I would be interested in viewing your forum. While my own experience is in glass science, my daughter is an avid glassblower. We have had many interesting discussions regarding color form our different perspectives. Perhaps I can contribute to your forum from my perspective as well.

James Shelby"

Does anyone know his daughter? Is she possibly a member of the forum?

This really made me smile
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