Higher-Silica Feldspar SiO₂ 75–85% REACH Compliant Responsible Mineral Supply

Microbrite®(S) Higher-Silica
Feldspar Supplier UK

Higher SiO₂ content (75–85%). Low Fe₂O₃ (0.10–0.20%). High dry brightness. Melting point >1100°C. Grades 2s, 5s, 15.

Product Overview

Why Switch to Microbrite®(S)?

Microbrite®(S) is manufactured from higher-silica content feldspar selected from the Limpopo pegmatite ore body — delivering a product with elevated SiO₂ content, high dry brightness, inertness and acid resistance.

For formulators of paints, industrial coatings, sealants, rubber compounds, plasters and thermosetting polymers, Microbrite®(S) offers a production-backed South African source — backed by responsible mineral supply with documented origin and traceability.

◆Elevated SiO₂ (75–85%) — inert, acid-resistant functional filler
◆Low iron (0.10–0.20% Fe₂O₃) — high dry brightness, suitable for white and light-coloured systems
◆UV and acid resistance — suited to exterior and acid-resistant formulations
◆Hardness Mohs 6 — contributes to scrub resistance and film hardness in coatings
◆Heat stability >1100°C — promotes strength, heat and acid resistance in thermosetting polymers
◆Versatile grade range (d50 6.8–27.6μm) — fine to medium particle sizing for diverse formulation requirements
◆Responsible mineral supply — documented origin and traceability from mine to UK delivery

Key Specifications

SiO₂75–85%

Al₂O₃9.0–11.0%

Fe₂O₃0.10–0.20%

K₂O / Na₂O5.0–8.0%

Specific Gravity2.59 kg/litre

HardnessMohs 6

Melting Point>1100°C

d50 Range6.8–27.6μm

Available Grades2s, 5s, 15

Packaging25kg packed bags & 1000kg bulk bags

OriginLimpopo Province, SA

Typical values. Contact us for specification confirmation.

Request Technical Documentation Request Sample

Grade Data

Particle Size Properties — Grades 2s, 5s & 15

All grades are milled and classified, with particle size quality-controlled by wet sieve analysis.

Property	Unit	Microbrite® 2s	Microbrite® 5s	Microbrite® 15
% Retained @ 25μm	%	< 2.0	N/A	N/A
% Retained @ 63μm	%	N/A	< 1.0	N/A
% Retained @ 106μm	%	N/A	N/A	< 2.0 **
Average Particle Size d50	μm	6.8	12.7	27.6
Oil Absorption	%	26	23	17
Reflectance	%	94	93	92
Bulk Density (As Packed)	kg/litre	0.70	0.85	0.93
Specific Gravity	kg/litre	2.59	2.59	2.59
Hardness	Mohs	6	6	6
Melting Point	°C	>1100	>1100	>1100

Mean values. These do not represent a specification. ** Quality controlled by wet sieve analysis.

Product Photography

Actual Grade Samples

Microbrite®(S) higher-silica feldspar from Limpopo Province, South Africa. Fine micronised grades for coatings, ceramics and technical glass applications.