A.K.A.: Tanacetum annuum, chamomile's cousin
Derived from: Blue tansy hails from Morocco and grows on a yellow-flowered plant (note: no blue!). Its deep aquamarine is only revealed after being extracted from the plant by steam distillation: You can thank the chemical compound chamazulene for the lovely hue.
Characteristics: Blue tansy in its purest oil form has a thick consistency that can stain clothes and skin if you're not careful. It has an aromatic, lightly sweet scent.
What it does: It's no wonder blue tansy has become a skincare ingredient darling—it's ultra-soothing and reduces irritation, which is useful if you suffer from eczema, psoriasis, dermatitis, or rosacea, but also if you just have that pesky don't-put-anything-on-me sensitive skin. If soothing is the oil's main property, its antibacterial, antihistamine, and anti-inflammatory properties are a close second.
Other uses: Traditional healers use blue tansy as an essential oil to soothe and treat burns and various other medical conditions. It's also purported to increase confidence—in other words, we'll now be using it daily before work.
Found in: In addition to its blue tansy mask, Herbivore Botanicals lassoes the ingredient in its Lapis Facial Oil, which hydrates and balances combination and oily skin while reducing redness and clarifying (perfect example of the ol' treat-oil-with-oil paradox—it actually works). Fan-favorite brand Sunday Riley's Blue Moon Tranquility Cleansing Balm uses blue tansy oil to kick irritation to the curb while the balm-to-milk formula removes makeup and cleanses skin—it can even be used as a mask for an ultra-deep clean.