Hey learned a little thing in my a&p class today. Its to test if your anemic, run a gold ring over your cheeck, if it leaves a black line your anemic. I dunno, maybe your feeling tired and you dont know why, give it a shot. If you know someone who is anemic, try it on them, its really neat to see.
I don't understand why?
Gold is a noble metal (i.e. does not react readily) thus there should not be any chemical reactions between your skin and gold.
The only thing I could think of is some sort of magnetic or electricial reaction may be causing the blackness.
Could you explain what is going on?
actually it was explained to me that doctors dont know why it works they just know that it works. No explanation yet
A noble metal? Say what? I was only under the impression that it was possible to have a noble gas, and that the reason they don't react is because all of their s and p sublevels are completely filled, thus making it difficult for them to gain or lose electrons. Gold, however, is a transition element, meaning that it has an f sublevel that is not completely filled, I believe.
Well that is pretty cool.
So only gold will leave a black mark? What about say iron or copper? You're not just physically brusing the skin (anemics maybe bruse easier)?
Noble not in absolute terms but in relative terms. Under most circumstances gold will not react. But under extreme circumstances (e.g. royal water, a strong mixture of nitric AND HCL acids) it will react. Hell under very extreme circumstances I think people have even got Neon to react.
Ok, here y'all go:
Black Dermographism is the name for this smudging. The term literally means "Black Writing on the Skin." It occurs when the cosmetics contain chemical compounds harder than the jewelry metals they contact. The most common of these compounds are zinc oxide, titanium dioxide, ferric oxide, and calamine. Zinc oxide is major white pigment used in face powder creams and lipstick. It has recently been replaced by titanium dioxide which can be equally hard on jewelry. Rouge and face powder often contain ferric oxide pigments, and calamine, a tinted zinc oxide, is found in some medicated cosmetics and lotions.
Particles from these cosmetics when left on the skin act like fine sandpaper. They abrade the softer jewelry metals -- gold, silver, platinum, or nickel. Such abrasion deposits a fine metallic powder from the jewelry metal on the skin. This powder looks black because the particles are too small to reflect light. The stain can be removed with soap and water.
To help do away with this problem women should remove rings while applying cosmetics. They should clean with soap and water those skin areas which touch jewelry.
The more precious the metal, the more discoloration produced on the skin, thus pure gold -- 24K -- readily smudges.
Some people do have sulfur in their sweat which produces a greenish-black stain when it contacts any metal jewelry. Such people should remove rings often and powder their fingers with an absorbent powder free of zinc oxide.
Sometimes, exposing the hands to salted nuts, crackers, or popcorn can cause such corrosion and discolor the skin.
Causes: Salt, Sulfur, and cosmetics. The latter, the worst offender. These also may stain rings or earrings.
I got this from the internet. There's a whole discussion thread about it. A lot of people seem to think that it's an indicator of anemia, but I would think that it's just having something on your skin or in dried sweat or skin oils that causes it. Perhaps anemics sweat something when they are low in iron, or develop something or other in their sebaceous glands? Who knows.
Lothario; fucken awesome man, good work, i was trying to find out why it did that. But yeah ive seen it work on anemics so i suppose the various compounds in sweat might do that but yeah... cool