Kaolinite

Kaolinite
General
Category	Phyllosilicates Kaolinite-serpentine group
Formula (repeatin unit)	Al2Si2O5(OH)4
Strunz clessification	09.ED.05
Creestal seestem	Triclinic
Space group	Triclinic pedial H-M seembol: (1) Space group: P1
Unit cell	a = 5.13 Å, b = 8.89 Å, c = 7.25 Å; α = 90°, β = 104.5°, γ = 89.8°; Z = 2
Identification
Colour	White, sometimes reid, blue or broun tints frae impurities
Creestal habit	Rarely as creestals, thin plates or stacked, Mair commonly as microscopic pseudohexagonal plates an clusters o plates, aggregatit intae compact, cleylik masses
Cleavage	Perfect on {001}
Tenacity	Flexible but inelastic
Mohs scale haurdness	2–2.5
Skinkle	Pearly tae dull yirdy
Streak	White
Speceefic gravity	2.16–2.68
Optical properties	Biaxial (–)
Refractive index	nα = 1.553–1.565, nβ = 1.559–1.569, nγ = 1.569–1.570
2V angle	Measurt: 24° to 50°, Calculatit: 44°
References

Kaolinite is a cley meeneral, pairt o the group o industrial meenerals, wi the chemical composeetion Al₂Si₂O₅(OH)₄.