Bismuth is the by-product of lead and copper refining, as well as other metals to a smaller degree. Bismuth occurs very rarely in nature. It is on the periodic table of elements under the symbol Bi at atomic number 83. It is very heavy and chemically resembles arsenic and antimony. It has a whitish/iridescent hue and has a very high shine property to it. Of all the heavy metals it is the only non-toxic. Bimsuth is a carrier for fuel in nuclear reactors. Bismuth components are used in everything from detection work, to making acrylic fibers, to safety devices in fire detection and extinguishing items, soldering, magnets and medicine as well as cosmetics. Because it is a by-product of lead refining, bismuth oxychloride should be lead free when companies begin using it in their cosmetics.
Companies use this in their cosmetics because it is cheap to buy and is an inexpensive filler. It does have binding qualities, so the makeup will "stick" to your skin, so to speak. There are other products that are just as effective at adhesion, and are better for your skin. Because of its molecular make up, it is often viewed as shiny or pearlescent. It is often sold in these two varieties. This makes it highly refractive, which is something companies want. Refraction will camouflage fine lines, wrinkles and discolorations. If you use a brand with bismuth oxychloride you'll notice a shiny look after applying the makeup. Not like oiliness, but almost shimmery. That's the bismuth oxychloride.
It's a very heavy element, which makes it difficult for many people to wear. It has to be forced into the pores (hence the buffing technique) otherwise it is capable of sliding off the wearer's face. The heaviness can result in clogged pores or irritated skin. Bismuth oxychloride often feels silky and not rough when rubbed between the fingers. Mineral makeup companies that do not use it have a lighter feeling makeup that usually blends into the skin better and with less effort.
Its molecular makeup is a crystalline shape, which may be a cause of the itchiness some women get when they wear it. Many women experience noticeable itching when they sweat. Don't forget it is also kin to arsenic, chemically. Your body will reject things it does not like, and if you'll get sick from ingesting arsenic, it would make sense that your skin would get irritated from having arsenic forced into it.
