Lead Crystal: Cellular Phone Signal Stopper?

Certainly lead crystal can and does block some of the electromagnetic spectrum for it is used to make shielded viewing ports into X-ray chambers. I will have to investigate if this extends to below visible light frequencies but I doubt it.

As it does little to block visible parts of the spectrum, I doubt that the filtering properties would go back up at rf. I also suspect that rf blockers tend to be conductive. But I'm prepared to be corrected.

Thanks for the comment guys. I see this isn't a cut-n-dried question.

A practical test of this would be to simply place a known lead crystal bowl over my phone on a table and see what happens, then place phone inside two bowls and compare results. I have some Steuben crystal pieces, but these are packed away right now, so not possible for me to do such a test.

Are all devices going to be the same? Wireless mouse for example? Never mind, bad example... sort of problematic to work the mouse whilst it is inside a glass bowl.

problematic to work the mouse whilst it is inside a glass bowl.

Just purchase a small one of these and place with the wireless mouse.

Shake the bowls and make the mouse dizzy...

I believe opacity to various frequencies will differ with the exact chemical composition. Of course the geometry and thickness of the vessel also matters.

.

Your familiarity with the ring suggests you might have some leaded crystal handy. Perhaps you could conduct a test on known leaded and unleaded crystal with a cell phone to see if it might be a useful indicator. If you do, please let us know the results.

The only article I could quickly find that gave me any spectrum absorbtion analysis of any leaded crystal glass only went down to the infrared spectrum. This implies to me that RF frequencies will not be significantly absorbed at all.

I would say no. Cell phone signals have a wavelength of about a foot. It barely even sees the glass bowl and besides, glass is not conductive.

Xrays have a billion times shorter wavelength and are affected by the atoms of a material themselves. The photoelectric absorption per unit mass is approximately proportional to (Z/E)^3, where E is the energy of the xray photon energy and Z is the atomic number of the element. This is why lead is a good absorber of xrays.

https://en.wikipedia.org/wiki/X-ray

there could be something to this "parlour trick"http://www.popsci.com/gadgets/article/2013-08/how-protect-yourself-your-phone

The link relates to woven fabric - with suggestions of conductive fibers in the weave (which I believe would be essential, unless the fabric was otherwise conductive). I don't see how this relates to glass.

the Faraday reference was clear to me

Lead glass is a very good insulator. I assume the man at the yard sale was thinking that the lead made the glass conductive. Lead glass actually contains lead dioxide.

https://en.wikipedia.org/wiki/Lead_glass

If you're worried about your phone getting turned on remotely, you can remove the battery. Or you can run the battery down...there's an app for that. Actually quite a few apps I have on my phone are pretty good at that.

What, do you want to update. I want to update. I'm going to update. I didn't update.

What, do you want to update. I want to update. I'm going to update. I didn't update.

What, do you want to update. I want to update. I'm going to update. I didn't update.

What, do you want to update. I want to update. I'm going to update. I didn't update.

What, do you want to update. I want to update. I'm going to update. I didn't update.

What, do you want to update. I want to update. I'm .... I didn't update.

What, do you want to update. I want to update. I didn't update.

What, do you want to update. I want to I didn't update.

What, do you want to update. I didn't update.

What, do you I didn't update.

I need to recharge. I want to update.

Drop your bowl in a measurement device. Beaker with volume indication.

Weigh your bowl.

Determine the density and look up which glass it fits.

The best lead crystal glass contains no more than 35% lead. That is not going to absorb any kind of radiation significantly.

For comparison, lead glass for X-ray shielding contains about 70% lead, and the panels have a thickness of 8 mm and upwards.

I seriously doubt any glass that was 70% (molecular or even by mass) lead would transmit visible light sufficiently well to be useful, even if it were only 8 mm thick.

.

AFAIK leaded glass used for shielding typically is comprised of up to around 30% (by mass) PbO.

Why do people proclaim things as untrue that can be easily searched for today. Particularly when the comment is a tangent to the original problem. Here they offer glass that is 55%~65% that have 88% visible light transfer.

Stating that I had a doubt and further making a statement preceded by AFAIK, is not the same as proclaiming something to be untrue.

I have never before seen lead glass for radiological controls outside around 30% pb.

Furthermore, I am a little fuzzy on how exactly 70% Pb would work for a transparent glass. It certainly can't on a molecular basis, as in glass, once again AFAIK, lead is on the form PbO...at best. So even if it was pure PbO that would cap out at 50%.

On a per mass basis, if the link is not in error, it appears to be available. I am not want to trusting just any website, so I'll dig a little further, but for now it does look like my initial doubt was not well founded.

.

Live and learn.

This glass has a content of 48% lead and 15% barium, and this glass has a content of over 70% lead.

I have no problem with 48% lead.

The second link, however, confirms my suspicion that trust is not well placed in random websites even if they are selling lead glass.

The second link lists the density of the glass as 4.3 grams /cc The density of PbO is over 9.5 grams/cc. The remaining 30% would have to be contributing negatively to density for anything under around 6.6 g/cc

.

I wouldn't put a lot of faith in just any website you find merely because the data supports your desired conclusion.

As I said before, if the comments were made concerning a per mass basis, it appears my doubts were unwarranted.....but that last link certainly didn't help to clarify.

It's a good point, and I'll check with my medical physics friends. My original comments in post #15 still stand, that the OP's crystal bowl was too thin and too deficient of lead to offer any significant radiation absorption.

Come now, let's stay on track here....you cannot compare radiowave transmission interference with gamma ray penetration. The % lead in the glass will influence the blocking of gamma, not radio.

I was too lazy to post that, it just seems so obvious

The bowl was actually fine lead crystal.

The cell phone guy obviously also wanted the bowl and saw a way to dupe you so that he could buy the "reject" bowl at a reduced price after you didn't want it.

This is seeming as likely the scenario as not. This may have been his ulterior motive.

I violated one of the cardinal rules for these yard/garage sales... NEVER put something down if you have decided that you want it.

We packed the bowl around for a while, put it down to inspect something else, walked off and forgot it. Went back to get it... Gone. Don't know who got it.

It sounds like this expedient field test has little merit... sort of what I thought. I'm moving right now, so unless I go to some store where lead crystal is sold and try this with a display piece, a physical test will have to wait for a while.

Thanks guys for the discussion and opinions.