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Product Description
Benefits & Application Details

Quartz (silica, SiO2) is the core mineral within the Sibelco group and can be found in a broad number of applications, such as glass, ceramics, filtration, construction,….. and polymers. 

 Sibelco has different capabilities to process quartz: 

  • Classifying quartz to obtain materials with specific certain granulation, but not milled nor calcined – the material is called Silica Sand. Products are called Silica Sand.
  • Milling, drying and classifying quartz – the material is called Quartz Flour. Products are called Silverbond (M). 
  • Milling, drying and classifying  high purity quartz – the material is called Fused Silica. Products are called Megasil FS. (for more information see elsewhere in the tool).
  • Calcining quartz (high temperature treatment – the crystal structure changes) – the material is called Cristobalite. If additionally milled it is called Cristobalite flour. Products are called Sibelite.
  • High temperature treatment of high purity quartz to obtain spherical particles – the material is called spherical silica and products are called Megasil SS (for more information see elsewhere in the tool)


Quartz can be characterised by:

  • Relatively high Mohs hardness of 7
  • Low electrical conductivity
  • Easy to wet
  • High inertness in various media
  • Shape (depending on the source, quartz particles can have an angular or more rounded shape)

Note when using quartz: depending on the particle size distribution of the product, it can be labelled (STOT RE 2 or STOT RE 1). For more detailed information, visit  www.safesilica.eu.


Basic properties

Property Value Unit
Moisture [%]
pH 7 [-]
Hardness (Mohs) 7 [-]
Refractive index 1.55 [-]
Colour (D65/ 10°) L* 93 – 96 [-]
L.O.I. < 0.3 [%]
Density 2.65 [kg/ dm3]


Silica Sand is the product name for Sibelco’s quartz-based products.



  • Coarse particles can provide anti-slip properties and texture
  • Excellent outdoor durability
  • Excellent chemical resistance
  • Excellent electrical insulating
  • Improved abrasion resistance


The majority of the fine grades are labelled STOT RE 2 or STOT RE 1 due to the presence of fine crystalline silica.


Silica Sand M grades contain very coarse grains and are therefore merely used in liquid roofing and flooring systems to render the surface anti-slip and durability.

Silverbond M grades are used in combination with one of Sibelco’s ATH grades in the epoxy-resin for encasing transformers (so-called dry type transformers).

Sibelco  offers a wide range of milled quartz and ATH products to allow the skilled formulator to select the best and most economical combination for the epoxy product delivering excellent performance in terms of the following properties:

  • Flame retardancy (ATH)
  • Mechanical strength (Silica)
  • Low viscosity (Silica and ATH)
  • Electrical insulation (Silica and ATH)
  • Thermal conductivity (Silica)


UV resistance and weatherability: due to its inertness, quartz supports good UV and weatherability performance to articles being used outside.


Due to its hardness of 7 on Mohs scale, quartz improves the wear and abrasion resistance of articles.


Chemical resistance: due to its inert nature, quartz provides good chemical resistance compared to conventional fillers.


Clarity: due to its fairly low refractive index, fine quartz grades become transparent when combined with certain binder systems.


UV-curing compatibility: being transparent for UV radiation, fine quartz grades do not block the curing mechanism.


IR reflection: quartz contributes to the IR reflection of liquid roofing systems .


Pore and grain filling properties (sealer): with low impact on the viscosity, quartz can be used as a mineral filler in sealers to give them more body.

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