Friday, September 30, 2011

Terry Smith of Signal Hill, California has some problem with yesterday’s “discovery” of “Window Glass Green”.

Alan,

I checked the Carder Steuben Club official website, and I see that there is no such mention of a “Window Glass Green” as there should not be in my opinion.

Are we not attempting to glorify examples of an inferior finished product, that we would not expect from Steuben glass? Has there been an kind of “study,” that would isolate a specific period of manufacture-time from which such examples are being found?

I am not a chemist, and know very little about the various ingredients used to make glass. But, when discussions have arisen about “sun-colored” glassware that was manufactured by a host-if-not-all glass companies, the ingredient “magnesium oxide” has been explained as a “preventative.” I have been “taught” that this specific ingredient was added/included in the formula intended to produce crystal-clear glassware, to prevent the “window glass green” situation.

The green appears, mostly, on the edges of common ordinary (PPG) plate window glass -and- even more-so on the edges of the thicker glass tabletops as mentioned by Mr. Bly. The “culprit” is the iron ore/oxide that is quite natural in even the finest grades of silica sand. Suppliers of the sand made efforts to removed as much of the iron, as possible. Glassmaker’s chemists discovered that the magnesium “neutralized” the effect of the minute amounts of iron, and the “window glass green” on the edges disappeared! What the chemists did not discover was long-range affect on the glass, containing minute amounts of magnesium, should the glassware be exposed to long periods of direct sunlight. I shall not comment on those people that like sun-colored glassware, and especially not on those individuals that purposely subject “old glass” to sunlight in-order to turn-it-purple on-purpose!

It is difficult for me to accept that Steuben, on-purpose, skimped on the ingredients . . . for any reason. More likely would be a situation where a trusted supplier shipped Steuben a load or loads of poorer-quality silica sand. The quality of the sand, and its levels of iron, were not discovered until after a batch or batches of glass were made. I would also like to think that Steuben would not sold such resulting finished wares as “first quality.”

Do we, as collectors, put a high-or-higher value on the (hopefully) limited quantity of these inferior pieces! Maybe some will, like the U. S. Postage stamps-or- various country’s currency/coins with printing/minting errors.

Terry Smith

www.cardersteubenclub.org

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2012 Carder Steuben Club annual Symposium will be held at The Corning Museum of Glass in Corning, NY from September 20-22, 2012.