Feldspar
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Introduction

Sibelco feldspar quarry in Cine (Turkey)
Feldspar is an aluminium silicate with chemical formula X(AlSi3O8), where X can be Na, K, and a wide variety of other metals. Na(AlSi3O8) is one of the main constituents of the Earth’s crust. Feldspar can be characterised by:
- Relatively high Mohs hardness of 6
- Low electrical conductivity
- Easy to wet
- High inertness in various media
And, depending on the grade:
- Low content of lamellar mica
- Low fine crystaline silica fraction (no labelling)
- Whiteness
Note when using feldspar: depending on the particle size distribution of certain products, they can be labelled STOT RE 2. For more detailed information, visit www.safesilica.eu.
Basic properties
| Property | Value | Unit |
| Moisture | < 0.5 | [%] |
| Hardness (Mohs) | 6 (6.5) | [-] |
| Refractive index | 1.53 | [-] |
| L.O.I. | 0.5 | [%] |
| Density | 2.6 | [kg/ dm3] |
Feldspar PGW micronised fillers are obtained from a naturally white, chemically inert product with a low free silica content and exceptionally low in soluble salts. Feldspar PGW is an economical and particularly effective solution as an antiblock additive in polymer film applications. Feldspar products are also used as an extending filler in resin systems and in elastomeric materials.








