Dolomite, mica, quartz and feldspar — functional extender fillers sourced from audited Indian producers and supplied to Australian and global paint formulators with full batch traceability.
Industry Overview
Mineral fillers are fundamental to modern paint and coatings technology. Far more than simple bulking agents, they actively influence rheology, barrier performance, scrub resistance, opacity, weatherability and cost. Selecting the right mineral — and the right mesh size — is as important as the binder system itself.
Paint formulators draw on a palette of mineral fillers, each contributing distinct functional properties. Dolomite powder extends pigment and lowers oil absorption. Muscovite mica creates a physical barrier that protects the binder from UV degradation and moisture ingress. Fine quartz powder builds scratch and wear resistance into industrial topcoats. Feldspar provides chemical resistance through its inherent hardness and alumina content.
PIME sources all four from established, audited producers in India — one of the world's most prolific sources of paint-grade minerals — and supplies them to Australian paint manufacturers, industrial coatings formulators and polymer compounders with a Certificate of Analysis (CoA) on every batch. Custom mesh sizes are available against confirmed orders.
Our Paint-Grade Minerals
Each mineral we supply addresses a specific technical requirement in paint and coatings formulation — from extending and cost-reduction to barrier protection and wear resistance.
Dolomite is widely used as an extender filler in architectural and industrial paints where cost-efficiency is a priority. PIME's currently stocked commercial-grade dolomite (CaO 30.2%, MgO 21.0%, Fe₂O₃ 0.36% — ALS-verified) is well-suited to tinted and architectural formulations. Pristine-white or low-iron paint applications require a lower-iron grade, which we can source on forward order against your specification.
Muscovite mica's unique platelet crystal structure makes it indispensable in coatings where long-term durability is critical. The overlapping platelets create a tortuous diffusion path that dramatically slows the ingress of water, oxygen and UV radiation through the coating film.
Micronised quartz powder adds functional hardness to industrial topcoats and floor coatings where scratch and abrasion resistance are primary performance requirements. With a Mohs hardness of 7, quartz is the hardest of the common paint fillers and directly contributes to the mechanical durability of the cured film.
Feldspar contributes hardness (Mohs 6–6.5) and chemical resistance to industrial coatings, particularly primers and mid-coats exposed to aggressive chemical environments. Its aluminium silicate composition provides inherent resistance to weak acids and alkalis, extending the service life of protective coatings.
Technical Comparison
Understanding how dolomite compares with the most common paint extender alternatives helps formulators make confident sourcing decisions.
| Property | Dolomite (PIME) | Ground Calcite (CaCO₃) | Talc (Mg₃Si₄O₁₀(OH)₂) |
|---|---|---|---|
| Chemical Formula | CaMg(CO₃)₂ | CaCO₃ | Mg₃Si₄O₁₀(OH)₂ |
| Mohs Hardness | 3.5 – 4.0 | 3.0 | 1.0 |
| Whiteness Index (%) | 90 – 94 | 92 – 96 | 85 – 92 |
| Oil Absorption (g/100g) | 14 – 18 (low) | 15 – 22 (low–medium) | 28 – 55 (high) |
| Density (g/cm³) | 2.85 | 2.71 | 2.75 |
| Platelet Structure | No (blocky/rhombic) | No (rhombic) | Yes |
| Barrier Effect in Film | Limited | Limited | Good |
| Cost Efficiency vs CaCO₃ | Favourable at equivalent whiteness | Baseline | Higher cost |
| Scratch Resistance Contribution | Moderate | Low | Very low |
| Alkaline pH Buffer | Yes — beneficial in anti-rust primers | Yes | Neutral |
| PIME Supply Grade | 325 / 500 / 635 mesh, CoA per batch | Not supplied | Not supplied |
Values are typical ranges. Exact specifications provided in Certificate of Analysis per batch. Contact PIME for product datasheets.
Technical Specifications
Every CoA issued by PIME reports the parameters that matter most to paint and coatings R&D and QA teams.
Critical Parameter
Reported as g linseed oil per 100 g mineral (ASTM D281). Low OAV means less binder consumed per unit volume — directly reducing formulation cost and improving film hardness at equivalent PVC. Dolomite typically 14–18 g/100g; quartz 18–22 g/100g.
Critical Parameter
Measured by reflectance spectrophotometer (ISO 2469). Directly determines the degree to which a filler supports TiO₂ efficiency. PIME dolomite targets ≥90%; quartz powder ≥92% whiteness.
Critical Parameter
Reported as mesh size (ASTM E11) and D50/D90 (laser diffraction, ISO 13320). Finer mesh means smoother films with better gloss; coarser mesh provides texture and abrasion resistance. PIME reports both mesh passing % and laser diffraction D50/D90 on every CoA.
Critical Parameter
Reported as % loss on drying at 105°C (ISO 787-2). Moisture above 0.5% can cause gassing in solvent-borne systems and premature gelling in some waterborne formulations. PIME specifies moisture <0.5% on all powder grades.
Why Choose PIME
Each shipment is accompanied by a full CoA covering chemical composition, fineness (mesh passing and D50/D90), whiteness index, moisture content and oil absorption value — so your QA team has the data it needs before the product arrives.
Standard grades are maintained in stock. Non-standard mesh sizes — including ultra-fine 1000 mesh and coarser texture grades — are available against confirmed purchase orders with appropriate lead time.
India holds some of the world's largest reserves of dolomite, mica and quartz. PIME works exclusively with producers who have been quality-audited and who supply consistent product across multiple production runs — not spot-market sources.
Smaller formulators can access 25 kg or 1 MT bag formats; larger manufacturers benefit from full container loads (FCL) at competitive landed costs into Australian ports including Sydney, Melbourne and Brisbane.
As an independently owned Australian trading house, PIME's team gives paint formulators direct access to sourcing decisions — no layers of intermediaries, no opacity on origin or production lot.
PIME can supply fine sericite mica (200–325 mesh) for decorative and architectural coatings alongside coarser flake mica (20–80 mesh) specifically graded for anti-corrosion primers and marine coatings — both from the same audited supply chain.
Common Questions
Oil absorption value (OAV) determines how much binder a filler consumes in a formulation. A lower OAV means more filler can be incorporated at the same binder level — improving cost efficiency and, at high PVC, producing a harder, more open film. PIME's dolomite powder (635 mesh) has a typical OAV of 14–18 g linseed oil per 100g, which is lower than many talc grades (28–55 g/100g) and broadly comparable to ground calcium carbonate. This makes dolomite an efficient, cost-effective extender in both water-borne and solvent-borne paint systems. Exact OAV is reported on the CoA for each production batch.
Both mica and talc are platy minerals that create a barrier effect in paint films, but they differ meaningfully in performance and cost. Mica (muscovite) has a Mohs hardness of 2.5–3 vs talc's 1, giving mica-containing coatings better scrub resistance. Mica's UV reflectance at the platelet surface is superior, making it the preferred choice for exterior architectural coatings where chalking resistance and durability under UV are priorities. Mica also reinforces the film mechanically, reducing cracking on thermal cycling — particularly valuable in anti-corrosion primers for steel structures. Talc is often selected for its extremely low OAV, its smoothness-improving effect in fine interior finishes, and its cost position. For exterior coatings, industrial primers and marine applications, PIME recommends muscovite mica; for interior matt emulsions where smoothness is paramount, talc may be preferable — though it is not currently in PIME's product range.
The appropriate mesh grade depends on the coating type and application method. For architectural exterior emulsions, 325–500 mesh dolomite or sericite mica (D50 ~10–15 µm) gives the right balance of smoothness, barrier performance and TiO₂ extension without visible grittiness. For industrial topcoats and floor coatings requiring scratch resistance, 200–325 mesh quartz powder (D50 ~20–35 µm) is typical. Anti-corrosion primers often incorporate coarser mica flake (40–80 mesh) alongside fine-ground dolomite or feldspar as complementary fillers. For high-build industrial coatings applied by airless spray, particle size must be controlled to prevent nozzle tip wear — PIME can advise on maximum D90 values for your application equipment. Contact our team with your formulation requirements and we will recommend the most appropriate grade.
PIME's standard minimum order quantity (MOQ) for paint-grade mineral fillers is 1 metric tonne (1,000 kg), supplied in 25 kg multi-wall paper bags or 1 MT bulk bags (FIBC/jumbo bags). For new customers and product development, we can supply laboratory samples (typically 2–5 kg) accompanied by a full CoA to support formulation trials prior to a commercial order. Larger development samples up to 100 kg can be arranged against a nominal sample charge. For full container load (FCL) orders, pricing is provided on a CIF or C&F basis to your nominated Australian port. Please contact us with your product requirements and annual volume estimate for a detailed commercial proposal.
Get Started
Tell us your application, mesh size requirements and approximate annual volume. PIME's team will respond with product specifications, CoA examples and pricing within one business day.