|Lime IS Calcium
|Re: Re: Re: Meeting, Etc. -- jake@nomaddesign
|Where am I?
When fakers want to make a new bead look like an old one, or to make an artificial product that realistically resembles a prototype, they have the best success if they reproduce the actions of nature and the technology of older times.
Then, it becomes up to us to make some distinction. I have already said that I can often visually tell the difference between the appearance of an ancient glass or stone bead, and a recent copy that has been trumped-up. However, I am not confident that I can characterize these differences in a way that communicates what I'm seeing and how you can see it too. But if we we can't tell the difference, we can't distinguish between authentic glass decay, and an ersatz treatment.
Part of the problem with what I hear you saying is that you don't seem to understand that lime and calcium are (essentially) the same thing. In natural/environmental glass-decomposition, if the lime is leached out, a white "deposit" (let's call it) evolves on the surface. This IS calcium. If a faker artificially decays some glass, it likewise will have calcium on its surface. Or, he/they may drip the bead into some concoction that places a calcium deposit onto the beads. Whatever it is, distinguishing between these is a lot harder than determining whether it's calcium or notóbecause it's ALL calcium. I expect it would take a chemist/glass expert to distinguish, probably using a handy microscope to examine the nature of the crystallization/structure. I think if you can see the difference with your unaided eye, an aided eye would be better. Then, there are probably lots of laboratory skills, about which I know nothing. (I watch all the CSI shows on TV every weekóbecause they fascinate me and are well produced, even though they don't reflect reality very honestly.)
By the way, Robert Liu produced an excellent article on glass decay for Ornament some years ago. I was happy to give him a bit of help with that. I highly recommend it. When glass decays (or is treated to decompose), depending on circumstances and and techniques, a lot of different-looking result may happen. But mainly, the glass is being attacked so that it falls apart (in different manners).
In the instance of stone beads, the story is similar. Constituents can be leached-out, and mineral deposits added. The so-called "etched agate" beads of antiquity and modern times are a great example of using a chemical (washing soda) to apply a desired pattern onto and into the surface of the bead (or object). We could think of this as "controlled partial patina," or something like that. When fakers want to artificially "age" new stone beads, they try to copy nature. If they place a calcium deposit onto the beads, this will look a lot like the natural/environmental effect found on ancient beads. And chemically it might be very similar.
As I saidóI am no chemist. So I'm not the guy to say much more than the above.