Boron nitride

What is it? Boron nitride is an inorganic compound made of boron and nitrogen, purchased in powder form for use in cosmetics.
INCI Boron nitride
Appearance White powder
Usage rate “Boron nitride is reported to be used at up to 25% in eye product formulations, at 2% in lipstick formulations, up to 16% in powders, and at up to 0.9% in fragrance preparations.” –CIR Report (These numbers were reported by industry as typical usage numbers and are not maximum allowable concentrations)
Texture Soft, fine powder
Scent None
Solubility Insoluble
Why do we use it in formulations? Boron nitride improves both slip and adhesion in cosmetics; I tend to primarily use it in eye makeup formulations as both slip and adhesion are very important there. It also contributes a bit of a soft-focus finish, similar to sericite mica. I’ve mostly worked with boron nitride in formulations you’ll find in my book, Make it Up.
Do you need it? Not necessarily, but I would highly recommend it if you want to make your own eyeshadow.
Strengths Excellent skin feel, slip, and adhesion properties.
Weaknesses Can be harder to find, and it is one of the more expensive cosmetic powders.
Alternatives & Substitutions Boron nitride is tricky to substitute. Sericite mica has similar properties, but does not improve adhesion nearly as well as boron nitride does, so you might consider using a blend of sericite mica and an adhesion booster like magnesium stearate or magnesium myristate as a starting point.
How to Work with It Include it in the ground portion of your cosmetic recipes. It can be hot or cold processed.
Storage & Shelf Life Stored somewhere cool, dark, and dry, boron nitride should last indefinitely.
Tips, Tricks, and Quirks The crystal shape of boron nitride is hexagonal.
Recommended starter amount 30 (1oz) or less. Even 10g (0.35oz) would last you a while if you can find somewhere selling that small of an amount.
Where to Buy it Buy it from an online DIY ingredient supplier. It is sold on Amazon, but much of it isn’t cosmetic grade, so if you do choose to purchase through Amazon please confirm with the seller that what you are purchasing is cosmetic and not industrial grade.

Some Formulations that Use Boron nitride

Ultramarines

What is it? Ultramarines are a synthesized pigment made from ingredients like kaolin clay and sulfur. The original blue pigment was ground from the semi-precious stone lapis lazuli, making it extremely expensive, and we’ve been synthesizing it since the early 1800s.
INCI Ultramarines
Appearance Vibrant fine pigments available in bright blue, lavender, and purple.
Usage rate I haven’t been able to find a maximum usage level. These pigments are very potent, though, so I can’t imagine you needing more than 50% for most cosmetics.
Texture Fine powder
Scent Generally nothing noticeable, though it can be sulfur-y in high-pH environments
Solubility Insoluble
Why do we use it in formulations? As pigments, for colour.
Do you need it? No, though if you are making cosmetics and want more natural bright blues and purples they are your only option.
Strengths Strong, vibrant pigments that are generally considered natural.
Weaknesses The blue in particular can be difficult to blend into formulas.
Alternatives & Substitutions Lake dyes are the only alternative for such bright, potent pigments.
How to Work with It Include in the grinding phase for powdered cosmetics or blend into melted creamy bases.

Ultramarine is not approved for lip use in the USA, but it is in the EU.

Storage & Shelf Life Stored somewhere cool, dark, and dry, ultramarine pigments should last at least five years.
Tips, Tricks, and Quirks Due to the sulfur used in the manufcature of ultramarines they can develop an eggy scent if used in products with a pH above 6.
Recommended starter amount 10g (0.35oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Ultramarines

Silica Microspheres

What is it? Silica microspheres is an “an amorphous hydrated silica” in a microsphere (super tiny ball) format. Silica is a naturally occurring mineral found in everything from granite to sand.
INCI Silicon Dioxide
Appearance Very fine white powder.
Usage rate 1–15%, up to 100% (watch for the product being too drying)
Texture Incredibly soft and smooth with a silky, dry finish.
Scent Nothing noticeable.
Solubility Insoluble
Why do we use it in formulations? Because they’re magic, basically. Silica microspheres improve slip, reduce the oily feel of products, and help improve the appearance of the skin by diffusing light for a real-life airbrushing effect.

I use silica microspheres in a lot of eye makeup formulas because they improve the slip/glide of the product and help with oil control, which helps improve wear time.

I include silica microspheres in cream cosmetics and oil serums because they give the end product a beautiful dry-touch finish that is incredibly luxurious and feels very expensive. Try blending a drop or two of oil with a tiny sprinkle of silica microspheres and rubbing that into your hand to see what I mean!

I love silica microspheres in all kinds of cosmetics for oil absorption, light diffusion, and improved slip.

Do you need it? If you want to make colour cosmetics I highly recommend owning some silica microspheres.
Refined or unrefined? Silica microspheres only exist as a refined product.
Strengths Extremely effective oil absorption, light diffusion, and improved slip.
Weaknesses They can be hard to find in some parts of the world, and may be too drying for some skin types.
Alternatives & Substitutions Silica microspheres are hard to substitute well. Sericite mica can be a decent alternative, but it is not nearly as oil absorbent so if the recipe relies on the silica microspheres for a dry-touch finish that likely won’t be present. Calcium carbonate has similar oil absorbing properties, but the pH is much higher so it isn’t a good choice for eye products. Calcium carbonate also has none of the light dispersion/blurring properties of silica microspheres.
How to Work with It Wear a dust mask! Silica microspheres are very lightweight and prone to floating around and being inhaled.

Stir or hand-mash into powdered cosmetics after you are done using your coffee grinder; grinding silica microspheres compromises their teensy sphere-ness. Silica microspheres can also be stirred into hot or cold liquid cosmetics that won’t be ground.

Storage & Shelf Life Stored somewhere cool, dark, and dry,
Tips, Tricks, and Quirks In my book, Make it Up, feel free to replace calcium carbonate with silica microspheres in any recipe for a better end result. I used silica microspheres sparingly in the book as they can be very expensive in some parts of the world, but if you have an ample supply I think you’ll enjoy the swap!

Some companies sell straight silica microspheres as an expensive setting powder—check your ingredient labels!

Recommended starter amount 30g (1oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Silica Microspheres

Magnesium Myristate

What is it? Magnesium Myristate is the salt of magnesium and myristic acid (a fatty acid that naturally occurs in palm and coconut oils).
INCI Magnesium Myristate
Appearance Fine white powder
Usage rate Typically 5–10% for loose powders. For creamy cosmetics and binding powders for pressing you’ll need to use it at higher rates.
Texture Magnesium Myristate is surprisingly creamy when handled—it has a wonderful, rich slip when rubbed between the fingers.
Scent Nothing much—perhaps a bit fatty or waxy.
Approximate Melting Point 130–150°C (266–302°F)
Solubility Oil, warm alcohol
Why do we use it in formulations? Magnesium Myristate gives our colour cosmetics both slip and adhesion—I find it provides more adhesion than the more readily available magnesium stearate. It can also used as a binding ingredient when pressing powders, but I tend to choose magnesium stearate over magnesium myristate for pressing as stearate is more readily available.
Do you need it? I highly recommend it if you want to make your own makeup—especially if you want to make items like eyeliner that have higher adhesion requirements than something like blush.
Refined or unrefined? Magnesium Myristate only exists as a refined product.
Strengths Excellent ingredient for increasing slip and adhesion/wear time in colour cosmetics—especially in more challenging products like eyeliners and lipsticks.
Weaknesses It is harder to acquire than magnesium stearate.
Alternatives & Substitutions You could try zinc stearate or magnesium stearate, but you will need to re-test the formula for performance and wear time.
How to Work with It Blend it in with the other powders in powdered cosmetics. In cream cosmetics it can be stirred into the oil phase. As with all fine powders, be sure to wear a dust mask if it going to be whipped up/aerosolized.
Storage & Shelf Life Stored somewhere cool, dark, and dry, magnesium myristate should last at least two years.
Tips, Tricks, and Quirks Try incorporating a small amount of magnesium myristate into a recipe for colour cosmetics that could use better wear time—it works incredibly well!
Recommended starter amount 30g (3oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Magnesium Myristate

Magnesium Myristate is a very commonly used ingredient in my book, Make it Up.

Magnesium Stearate

What is it? Magnesium Stearate is the salt of magnesium and stearic acid.
INCI Magnesium Stearate
Appearance Fine white powder
Usage rate Typically 5–10% for loose powders. For creamy cosmetics and binding powders for pressing you’ll need to use it at higher rates.
Texture Magnesium Stearate is surprisingly creamy when handled—it has a wonderful, rich slip when rubbed between the fingers.
Scent Nothing much—perhaps a bit “fatty”
Approximate Melting Point 130°C (266°F)
Solubility Oil, warm alcohol
Why do we use it in formulations? Magnesium Stearate gives our colour cosmetics both slip and adhesion. It is also used as a binding ingredient when pressing powders.
Do you need it? Magnesium Stearate is essential if you are making your own makeup.
Refined or unrefined? Magnesium Stearate only exists as a refined product.
Strengths Excellent, inexpensive ingredient for increasing slip and adhesion/wear time in colour cosmetics.
Weaknesses I can’t think of any!
Alternatives & Substitutions You could try zinc stearate or magnesium myristate, but you will need to re-test the formula for performance and wear time. I do not recommend eliminating this ingredient as both slip and adhesion are crucial to the success of colour cosmetics.
How to Work with It Blend it in with the other powders in powdered cosmetics. In cream cosmetics it can be melted into the oil phase, but I’ve also found if that it incorporates well if pre-ground with the other powders and stirred into the creamy base.
Storage & Shelf Life Stored somewhere cool, dark, and dry, magnesium stearate should last at least two years.
Tips, Tricks, and Quirks Stearic acid is almost always vegetable derived, but it is possible to source it from animal fats as well. Double check with your supplier if they don’t state the origin—that said, I have never found magnesium stearate made with animal-derived stearic acid.
Recommended starter amount 30g (1oz)
Where to Buy it  Buy it from an online DIY ingredient supplier or Amazon.

Some Formulations that Use Magnesium Stearate

Isododecane

What is it? Isododecane is an extremely lightweight, very volatile (fast evaporating) liquid. It is an emollient and solvent that is frequently used in cosmetics. It gives a fantastic dry-touch finish very quickly.
INCI Isododecane
Appearance Water-like clear liquid.
Usage rate Up to 20%
Texture Thin liquid with great slip, very fast evaporation, and great leftover skin feel.
Scent Nothing noticeable
Absorbency Speed Very fast evaporation
Solubility Soluble with silicones, hydrocarbons, isoparaffin, and mineral spirits.
Why do we use it in formulations? Isododecane is incredibly useful in liquid cosmetics—I’d call it indispensable. It is an excellent choice for liquifying cosmetics that we need to set quickly (liquid lipstick, liquid eyeliner, etc.) as it sets quickly but spreads beautifully before setting. It is also an excellent solvent for strong film-forming silicone resins like trimethylsiloxysilicate.
Do you need it? If you want to make liquid cosmetics it is necessary.
Refined or unrefined? It only exists as a refined product.
Strengths Fantastic fast-evaporating emollient.
Weaknesses Not natural if that is a priority for you. Low flash point (43°C/109°F).
Alternatives & Substitutions Nothing, really. Cyclomethicone is also slippy and volatile, but doesn’t have the same dry-touch finish as isododecane and that finish can be absolutely instrumental to the performance of cosmetics like liquid lipsticks and eyeshadow primers.
How to Work with It Include it in the cool down phase of your recipes. If necessary, very briefly heat it to incorporate it into pre-melted waxes. Keep the flash point (43°C/109°F) in mind! Don’t forget to replace the lid promptly—it will evaporate if left uncovered!
Storage & Shelf Life Stored somewhere cool, dark, and dry, isododecane should last at least two years.
Tips, Tricks, and Quirks Its weightless feel and fast evaporation speed make it an excellent addition to many products where we want great spreadability but no residual weight—think cosmetics and hair products.

Isododecane is a great solvent, which makes it fantastic for cleaning up hard-to-clean messes! I find it brilliant for cleaning up stubborn smudges of colourful cosmetics.

Recommended starter amount 250mL (8fl oz)
Where to Buy it  Buy it from an online DIY ingredient supplier.

Some Formulations that Use Isododecane