• INCI Name: Hydrated Silica
• CAS Number: 7699-41-4 (hydrated silica) / 112926-00-8 (amorphous precipitated silica)
• Chemical Formula: SiO₂·nH₂O
• Common Names: Precipitated Silica, Hydrated Silica, Amorphous Silica, Synthetic Amorphous Silica
• Grade: Cosmetic Grade / Food Grade (E551)
• Form: Hydrated and Precipitated (amorphous, non-crystalline)
• Crystalline Silica Content: None — amorphous form only; not associated with silicosis risk at cosmetic use concentrations
• Appearance: White ultra-fine free-flowing powder
• Odour: Odourless
• Taste: Bland, neutral (food grade)
• pH (5% suspension in water): Approximately 6.5–7.5 — near neutral
• Specific Surface Area: 150–300 m²/g (very high — responsible for oil absorption and thickening properties)
• Oil Absorption Capacity: 200–300 g oil/100g silica
• Particle Size: Ultra-fine — typically 1–20 microns average primary particle size
• Solubility: Insoluble in water, organic solvents, and most cosmetic vehicles
• Refractive Index: Approximately 1.46 (compatible with many cosmetic systems — near-transparent in appropriate formulations)
• Bulk Density: Approximately 0.05–0.15 g/cm³ (very low — fluffy, high-volume powder)
• Storage: Store in a tightly sealed container in a cool, dry place away from moisture
• Shelf Life: Indefinite in properly sealed, dry storage

HOW IT WORKS — THE SCIENCE

Precipitated Silica's extraordinary functionality comes from its three key physical properties:

1. Exceptionally High Surface Area
The precipitation process creates a highly porous, irregular particle structure with a surface area of 150–300 m²/g — meaning a single gram of precipitated silica has more exposed surface area than a tennis court. This vast surface area is what drives its oil absorption, thickening, and suspension capabilities. Every available surface site can interact with surrounding molecules, creating a matrix that traps and holds oils, thickens liquids, and prevents settling.

2. Oil Absorption Capacity
At 200–300g of oil absorbed per 100g of silica, precipitated silica is one of the most effective oil absorbers available for cosmetic use. In dry shampoo it absorbs sebum from hair; in mattifying formulations it absorbs skin surface oil; in powder cosmetics it prevents the powder from feeling greasy or clumping due to oil contamination.

3. Thickening and Suspension in Liquids
When dispersed in liquid vehicles, precipitated silica particles form a three-dimensional network that significantly increases viscosity and prevents settling of other particles. This is the mechanism behind its use as a thickener in gels and as a suspension agent keeping active ingredients uniformly distributed.

RECOMMENDED USAGE RATES

Toothpaste and Oral Care (abrasive)

• Hydrated Silica: 10–25% of total formulation
• Functions as the primary gentle abrasive for plaque removal and polishing
• Compatible with fluoride-containing formulations

Toothpaste and Oral Care (thickener/texture)

• Hydrated Silica: 2–8% as a viscosity builder and texture modifier in gel toothpaste

Dry Shampoo

• Precipitated Silica: 5–20% of total dry formulation
• Absorbs scalp oil and sebum; blends well with cornflour, arrowroot, and starches
• Tip: Higher silica content (15–20%) for very oily hair; lower (5–10%) for normal hair types

Mattifying Primer and Foundation

• Precipitated Silica: 2–8% in pressed or loose powder formulations
• Absorbs skin surface oil for extended matte finish; improves slip and skin feel

Natural Deodorant Powder

• Precipitated Silica: 2–10% as a moisture and odour absorber
• Works synergistically with arrowroot and cornflour

Pressed Powder Cosmetics (eyeshadow, blush, setting powder)

• Precipitated Silica: 1–5% as a flow agent, binder, and anti-caking agent

Gel Thickener (aqueous gels)

• Precipitated Silica: 1–5% to increase viscosity and create a gel-like consistency in water-based formulations
• Produces a thixotropic gel (flows under shear, sets on standing)

Suspension Agent

• Precipitated Silica: 0.5–3% to prevent settling of heavy particles (mica, pigments, zinc oxide) in liquid formulations

Anti-Caking Agent in Powder Blends

• Precipitated Silica: 0.5–2% added to any dry powder blend to improve flow and prevent clumping

• Functionally multifunctional — serves as thickener, oil absorber, flow agent, gentle abrasive, mattifying agent, anti-caking agent, and suspension aid in a single ingredient
• The standard gentle abrasive in toothpaste and oral care formulations — removes plaque effectively without damaging tooth enamel; RDA (relative dentin abrasivity) of approximately 7–15 (very gentle) compared to baking soda (RDA ~70) or pumice (RDA ~100+)
• Exceptionally high oil absorption capacity (200–300g oil/100g) — superior sebum absorption in dry shampoo and mattifying formulations
• Near-neutral pH — compatible with all cosmetic formulations without disrupting pH balance
• Odourless and tasteless — completely neutral in oral care and cosmetic applications
• Amorphous form — not associated with the crystalline silica respiratory hazards of industrial quartz; safe for cosmetic use
• Refractive index of approximately 1.46 — appears nearly transparent in many cosmetic systems, avoiding the white cast of high refractive index powders
• Very high surface area produces thickening effects at low usage rates — cost-effective as a thickener and suspension agent
• Food grade (E551) — approved for oral care, lip products, and food applications
• Insoluble in all cosmetic vehicles — provides consistent physical performance regardless of formulation type
• Compatible with all cosmetic ingredient classes — works alongside surfactants, emulsifiers, actives, pigments, and preservatives

PRECIPITATED SILICA vs FUMED SILICA vs CRYSTALLINE SILICA

Understanding the differences between silica types is important for safe and effective formulation:

Precipitated Silica (this product): Made by controlled precipitation from sodium silicate. Amorphous structure. Relatively soft particles. Lower surface area than fumed silica. Primary uses: toothpaste abrasive, dry shampoo, oil absorber, powder cosmetics. Safe for cosmetic use.

Fumed Silica (Aerosil): Made by high-temperature combustion of silicon tetrachloride. Extremely fine particles, ultra-high surface area (200–400 m²/g). Used primarily as a thickening agent in anhydrous systems (lip balm, lip gloss, serum thickeners). Different particle structure from precipitated — more effective as a rheology modifier in oil-phase systems. Not covered by this product listing.

Crystalline Silica (Quartz/Sand): Naturally occurring mineral silicon dioxide. Crystalline (regular atomic structure). Used in industrial applications and as coarse abrasives. The crystalline form is the type associated with silicosis when inhaled in occupational dust exposure. NOT used in cosmetics. NOT this product.

Our product is Precipitated Silica (amorphous) — the cosmetic-appropriate form.

TYPICAL APPLICATIONS

• Toothpaste and gel toothpaste (abrasive and thickener)
• Whitening toothpaste
• Natural and fluoride-free toothpaste
• Dry shampoo sprays and powders
• Mattifying primers and foundations
• Pressed powder cosmetics (eyeshadow, blush, contour, bronzer)
• Loose setting powders
• Natural deodorant powders and sticks
• Body powders and talc alternatives
• Aqueous gel thickening
• Suspension agent for pigments and actives
• Anti-caking agent in dry powder blends
• Lip balm (minor oil absorber in anhydrous systems)

• Cosmetic grade — safe for intended cosmetic and oral care applications at recommended concentrations
• Amorphous form — not associated with the crystalline silica respiratory hazard of industrial quartz; distinct from crystalline silica in both structure and safety profile
• Inhalation precaution: use a well-fitted dust mask when handling in bulk quantities — any fine powder in sufficient concentration can cause mechanical irritation of the respiratory tract; standard powder handling precautions apply
• Avoid contact with eyes; if contact occurs rinse thoroughly with water for several minutes
• Food grade (E551) — approved for oral care and limited food applications; safe for lip products with oral exposure
• Keep out of reach of children
• Store sealed away from moisture — absorbs atmospheric moisture which can affect performance; reseal immediately after use
• Environmental: amorphous silica is considered environmentally benign; not acutely toxic to aquatic organisms at cosmetic release concentrations

What is the INCI name for Precipitated Silica?
The correct INCI name is Hydrated Silica. This is the name that appears on toothpaste and cosmetic product ingredient lists globally, and is the name required on Australian cosmetic product labels under AICIS requirements.

Is Precipitated Silica safe to use in toothpaste?
Yes — Hydrated Silica is the most widely used abrasive ingredient in commercial toothpaste globally, including major brands available in Australian supermarkets. It has a very gentle RDA (relative dentin abrasivity) of approximately 7–15, making it safe for daily use without damaging tooth enamel. It is approved in both fluoride and non-fluoride toothpaste formulations and is compatible with all other standard toothpaste ingredients.

How is Precipitated Silica different from the silica in sand or quartz?
Quartz (crystalline silica) has a regular, ordered atomic structure and is the form associated with silicosis when inhaled in occupational dust concentrations. Precipitated silica (amorphous silica) has an irregular, disordered atomic structure produced by a controlled manufacturing process. The amorphous form does not present the same respiratory hazard as crystalline silica. All cosmetic-grade silica products, including this one, are amorphous — not crystalline.

How do I use Precipitated Silica in dry shampoo?
A simple dry shampoo formula: 50–60% arrowroot powder or cornflour + 15–20% precipitated silica + 10–15% kaolin clay + optional: 5% sodium bicarbonate, essential oil, or colourant for brunette tones (cacao powder or activated charcoal). The silica provides the primary oil absorption; the starch contributes bulk, skin feel, and secondary absorption; the clay adds further oil control and mattifying effect. Apply a small amount to roots, massage in, leave 1–2 minutes, then brush or shake out.

Can I use Precipitated Silica in gel formulations?
Yes — precipitated silica can thicken aqueous gels at 1–5% by forming a three-dimensional silica network in the water phase. The gel produced is thixotropic — it flows under shear (when squeezed from a tube or stirred) but sets back to a gel on standing. For anhydrous systems (oil-based gels, lip gloss thickening), fumed silica (not this product) is generally more effective due to its higher surface area. For water-based gels at low usage rates, precipitated silica is a functional and cost-effective option.

Is there a risk of breathing in Precipitated Silica?
As with any fine powder, standard precautions apply when handling precipitated silica in bulk — wear a well-fitted dust mask, work in a ventilated area, and avoid generating unnecessary airborne dust. At cosmetic formulation quantities and usage rates (grams to hundreds of grams), the risk is low. The product is amorphous silica — not crystalline silica — so the specific occupational silicosis risk associated with industrial crystalline silica dust does not apply. Exercise sensible powder handling precautions regardless.

YOU MAY ALSO NEED

• Arrowroot Organic Powder — blend with silica in dry shampoo, body powder, and deodorant formulations
• Cornflour (Wheaten) — cost-effective bulk base to blend with silica in dry shampoo and powder cosmetics
• Activated Charcoal Powder — add to silica-based dry shampoo for dark hair tones; also used in toothpaste formulations
• Kaolin Clay (Australian) — pairs with silica in dry shampoo, deodorant powders, and mattifying face masks
• Sodium Bicarbonate (Food Grade Baking Soda) — blends with silica in natural deodorant powder formulations
• Essential Oils Collection — scent your dry shampoo and powder formulations
• Peppermint Essential Oil — classic addition to silica-based natural toothpaste formulations