Saturday, September 12, 2009

Mineral make-up ingredients: Talc

As I mentioned yesterday, I was really surprised by the talc, so I had to write a post about it!

Talc is hydrous magnesium silicate with a chemical formula of Mg3Si4O10(OH)2 or H2Mg3(SiO3)4. It is the softest known mineral. It is used a lot in mineral make-up and most comparisons of fillers include "better than talc" or "not as good as talc" because it's been a staple for years.

Want a very technical link on talc? Here it is!

What are the benefits of talc in mineral make-up? It is hydrophobic. It absorbs moisture, acts as a lubricant, offers a slippery feel and increases spreadability, offers low covering power as it is translucent, and may offer some lustre without "undue glitter". You want to choose a talc with less than 200 mesh as this will feel smooth on your skin. Ironically, the smaller mesh sizes offer some grittiness, so micronized talc is probably not a great idea for mineral make-up.

What are the benefits for your skin? Talc can soothe inflamed or irritated skin, help with chapped skin or skin suffering from heat rash, and works as an oil absorber. It does this by creating a "shield" to protect your skin from the outside world (or as we know it, talc is occlusive). You can use talc as the main filler or use it as a substitute for the oil absorbers, calcium carbonate, starches, or kaolin clay.

Talc can be used at up to 70% as a filler for mineral make-up. You can find it in various forms, including delaminated talc. (Which, as far as I can gather, means it has been taken out of the fine, alternating layers of minerals (called lamellae) and made into another form. Hey, I haven't taken inorganic chemistry yet!) Any product made mostly with talc is going to have low lustre, low covering power, and great slip and glide.

And it's inexpensive. At $5.00 for 4 ounces, it's the most inexpensive filler out there (except, perhaps for calcium carbonate, and you aren't going to use that as the primary filler in anything!) You can use it as the filler for any mineral make-up product, even anhydrous products as it plays well with oils.

And no, I'm not talking about talcum powder. Talc is only one of the ingredients in talcum powder, the others being starches and other absorbers or slippery things to make it feel nice. If you do buy some talc, try making a nice talcum powder for yourself for those really hot days! You'll be happy you did!

Join me tomorrow for some experiments with talc!


Anonymous said...

This is interesting. I worry about talc in makeup because I've read that it is a known carcinogen. Is the pure mineral talc not toxic? It would be nice to know since I've just spent $ on a supposedly "all-natural" and "safe" liquid foundation.

Susan Barclay-Nichols said...

I offer you this link for information talc and cancer from PubMed and this link from the American Cancer Society. I consider both of these links credible sources.

The gist? The first article states there is "no credible evidence of a cancer risk from inhalation by humans". The second article indicates there may be some suggestion of an increase in ovarian cancer, there are no other forms of cancer associated with talc.

So what does this mean? I interpret this to mean talc is safe as used in mineral make-up products, and should be considered non-toxic. You should only be getting pure, cosmetic grade talc in your products - it's been the law since 1973 that talc needs to be asbestos free - which would be non-toxic.

By definition, talc is natural - it is a naturally occurring mineral. It is an inorganic compound, which means if you see the phrase "all organic talc" it's not only wrong on the common definition of "organic", but also from a chemistry definition!

Christine Sweet said...

I've been intrigued by the idea of liquid talc and wondering if it makes sense to add it to my favorite lotion recipe. Is that counterproductive? Does that even work? What would it do in a lotion? Thanks so much! We've gleaned so much info from you site and e-books!

Susan Barclay-Nichols said...

Hi Christine. It makes sense, but I have no idea how you'd do it as I've never heard of liquid talc. I encourage you to talk to your supplier and see what they suggest, then do an experimental batch. Please come back here and let us know how it turned out!