Why Is Milk White?: & 200 Other Curious Chemistry Questions (2013)
3. Household Chemistry
Why is lipstick so glossy?
Mica. Lipstick is a soft crayon made of waxes like beeswax, carnauba wax, or candelilla wax, vegetable oil, and pigments. Lanolin is sometimes added, and talc is sometimes used also. Vitamin E is added to protect the vegetable oils from going rancid. But to make the lips shine, tiny flakes of the mineral mica are added. Mica gets its name from the Latin word for “shine.” The shiny gold flakes you see in sand at the beach are made of mica.
Matte lipsticks are mostly wax and pigment. Sheer lipsticks have less pigment. Glossy lipsticks have (in addition to mica) more oil and sometimes use a silicone-based oil to be longer lasting. Frosted lipsticks have a pearlizing compound made of bismuth oxychloride.
Other glossy compounds used are diisostearyl malate and triisostearyl citrate. These are esters, which are compounds made from alcohols and acids, in this case the fat called stearic acid. They give a wet look to the lip gloss.