Castor oil is one of the most common ingredients used. Mostly because it does not cause or worsen acne on the skin. Synthetic Iron oxide (rust), is used to produce reds in modern cosmetics. Carminic acid also creates a deep red and is extracted from crushed Cochineal insects. Pearlescence is derived from the mineral Mica coated with Titanium Oxide, or crushed fish scales. This ingredient causes a shine or glossing effect. Foundation is used to conceal blemishes and complexion imperfections of the skin. It also provides a base for other products to adhere to. It usually contains a mixture of minerals, like Talc and Silica, to create different skin tones. Botanical ingredients include plant extracts or synthetics that mimic specific plant compounds to create the same effect. These are most often found in perfumes and added to products for fragrance.
According to the Food, Drug, and Cosmetic Act (Chapter VII, section 721), color additives, excluding coal tar hair dyes, must be approved before they can be used in food, cosmetics, drugs, or medical devices. Cosmetic color additives are regulated to ensure that they contain no heavy metals like lead or mercury which are poisonous.
This table provides an approved list of color additives for use in cosmetics.
http://www.fda.gov/Cosmetics/Labeling/IngredientNames/ucm109084.htm
