Rubber / Rubber Compounding / Quartz


Mineral: Silica


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 and polymers. 

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


Basic properties

Property Value Unit
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]



Name Grade D50
Silica (EU) M400 12
M500 5
M600 5
M800 1.8
Silica(APAC) 915 3


Production Location: Dessel (BE), Maastricht (NL), Brassington (UK), San I (TW)

Application: Silica has good electrical insulating properties and heat conductive properties. It can also lower the viscosity of the compound.

Functionalities: Performance

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