MIRROR: Download from MEGA
Karat Gold is not really hypoallergenic. Gold used in jewelry is almost always 14k or at best 18k gold ALLOY. It is actually against federal law in the US to use the terms "solid gold", "real gold" or "pure gold" when talking about anything other than 24 karat pure gold as it comes from the ground. 14 k gold is is actually an alloy composed of 57 percent real gold, and 43 percent copper. White gold is alloyed with nickle, and nickle is the most common metal allergy in the world. Sterling silver is 92.5 percent silver and only 7.5 % copper (or more rarely, nickle). This is why you will often see the advert :"Nickle-Free Silver!" Now, only Mexico and China routinely use nickle in their Sterling. Thailand, Isreal and Italy pride themselves on very good quality nickle-free Sterling.
Very few people are allergic to pure silver and most don't react to the small amout of copper in Sterling Silver. Pure silver is very soft, softer even than pure gold. A small amount of copper added to other metals has the interesting effect of making the combination harder than either of the metals alone.The 7.5 % copper added as a to silver makes it much harder and that 7.5% copper is what makes silver, by definition, "Sterling" Silver.
Stainless/surgical steel, pure 24k gold, pure silver and titanium are about the only metals that the body does not normally reject. Although 18 and 22k yellow gold are also well tolerated by the body.
Um, have I mentioned that I've been a jeweler?
Most plastics/acrylics are completely inert and do not cause problems with rejection. Their problem is they are much harder to render reliably sterile since they don't tolerate boiling or autoclave/hi-temp steaming. Chemical strerilization such as alcohol or other 'dips' are more expensive. By the way, alcohol cannot "cause" an infection. What alcohol does do is dry out the skin with repeted applications and can, if used too much, cause damage to the skin by drying it out to the point that it is easier for an oportunistic microbe (such as those on earrings that you may be trying on in the store?) to get established.
The "alcohol causes infections" thing is a myth started by companies who sold cleaning kits for piercings, including ears.
There! Way the hell more than you ever thought you'd need to know about the metalurgy of jewelry.
Fileboom Premium Account
Keep2share Premium PRO Account