Kaolinite

Kaolinite is a layered silicate clay mineral which forms from the chemical weathering of feldspar or other aluminum silicate minerals. It is usually white, with occasionally a red color impurity due to iron oxide, or blue or brown from other minerals. Kaolinite has a low shrink–swell capacity and a low cation-exchange capacity, making it ideal for many industrial applications.

Type

Mineral

Mineral Classification

Phyllosilicates

Chemical Formula

Al2Si2O5(OH)4

Streak

White

Mohs Hardness

2–2.5

Crystal System

Triclinic

Color

White, sometimes red, blue or brown tints from impurities

Luster

Pearly to dull earthy

Fracture

Irregular/uneven, conchoidal, sub-conchoidal, micaceous

Description

Kaolinite is a layered silicate clay mineral which forms from the chemical weathering of feldspar or other aluminum silicate minerals. It is usually white, with occasionally a red color impurity due to iron oxide, or blue or brown from other minerals. Kaolinite has a low shrink–swell capacity and a low cation-exchange capacity, making it ideal for many industrial applications.

Uses

During 2013, 48% of Kaolin was used in paper production, and 52% was used for ceramics, light bulbs, paint, rubber, adhesives, smoking pipes, white wash in masonry, absorbents, and in soap.  Within organic farming kaolinite is used as a form of pest control. It is an active ingredient within medicines for diarrhea, nausea, and other digestive issues.