Mineral makeup is popular in part because of its coverage- natural, smooth, and long-lasting. But how does it get that way? The formula derives these properties because the minerals are pulverized or "micronized" by companies into microscopic or even nanoparticle size. There are some researchers who say this process may come with a price to the consumer.
Jane Houlihan, research director of consumer watchdog agency The Environmental Working Group in Washington says, "Research shows that when some molecules are dramatically reduced in size to the level of a nanoparticle, they can have very different and very toxic properties than that same molecule would have in its conventional size." Houlihan continues, "Minerals like zinc and titanium are safe when applied to healthy skin but in a micronized nanoparticle form, there remains a concern, particularly when applied to damaged skin, or when inhaled."
Something else to consider is that the world mineral does not necessarily imply that the substance is all natural and derived from the earth. For example, bismuth oxychloride is a pearlizing agent that gives mineral makeup that "candlelight glow". This substance is a mineral by definition, but it is not found in the earth. Bismuth results as a byproduct of lead and copper processing. Bismuth oxychloride is commonly used to bind, "bulk up" or fill products, however some say you can pay a heavy pricetag for it.
Bismuth oxychloride is considered a skin irritant. It can cause rashes and itching to the skin. In large quantities, it can cause cystic acne as well. If you have acne, sensitive skin, or rosacea, it's one of the ingredients you should try to avoid. Keep in mind that some products in a line of mineral makeup may containvthis ingredient, while others don't. Some products may also contain such a small quantity of the mineral that it won't actually irritate your skin. There's really no way to know if you will have a reaction unless you try it.
The moral of this story is that even when a beauty product has "mineral' in its name (or actually contains minerals from the earth) it's still important for you to research and investigate the mineral product as you would traditional makeup products.