| Original Message: Re: Possibly a Glass Myth |
|---|
|
Hi Joyce, Most beads that are purple or violet were made that color by intent. Formulas for violet glass have been widely known since the early 17th C. (thanks to Neri), and were produced as early as 2,000+ years ago. It has been suggested that some glasses, because of their manganese content, will tend to turn reddish or violet over time. I don't know if this has been demonstrated or not. Manganese oxide is added to glass to counter-act the strong tendency for glass to be green because of naturally occurring iron impurities. The iron makes the glass green; the manganese makes the glass reddish. Together, they neutralize one another, and make the glass more colorless. Traditionally, this application of manganese has been called "glass soap," because it "cleans" the glass. A kitchen demonstration. I LOVE pesto and eat it (in something) nearly every day. Pesto is green, being made from fresh basil. A dish I enjoy making and eating is paste al pesto with shrimps and red peppers. The shrimps are pink and the peppers red. If you put these in pesto and cook them for a few minutes, the paste are no longer green.... Manganese is also a violet colorant for glass. It produces a muddy or brownish violet color on the red end of violet, but is probably combined with or otherwise manipulated to give a better color (purple being a desirable outcome, that few other colorants easily provide). I suppose it's possible that a surplus of manganese might unintentionally make some glasses tend to become reddish or purplish. However, I doubt the outcome would be the nice lavender purple we see in the beads in question. Jamey All rights reserved by Bead Collector Network and its users |
|
|