Aliettite

Aliettite is a complex phyllosilicate mineral of the smectite group with a formula of (Ca_0.2Mg₆(Si,Al)₈O₂₀(OH)₄·4H₂O)[1] or [Mg₃Si₄O₁₀(OH)₂](Ca_0.5,Na)_0.33(Al,Mg,Fe²⁺)_2–3(Si,Al)₄O₁₀(OH)₂·n(H₂O).[2][3]

Aliettite
Aliettite
General
Category	Phyllosilicates
Strunz classification	9.EC.60
Crystal system	Hexagonal Unknown space group
Unit cell	a = 5.216, c = 24.6 [Å]; Z = 1
Identification
Color	Colorless, pale yellow or green.
Crystal habit	Platy
Mohs scale hardness	1–2
Luster	Earthy (dull)
Streak	White
Diaphaneity	Translucent
Refractive index	1.558–1.567
References	[1][2][3][4]

It is a soft, colorless to pale yellow or green earthy mineral which crystallizes in the monoclinic system as minute tabular to platy crystals.[1]

It was first described in 1968 for an occurrence in Monte Chiaro, Albareto, Parma Province, Emilia-Romagna, Italy and named for the Italian mineralogist Andrea Alietti (born 1923).[1]

It occurs in serpentinized ophiolites and their residual soil. It also occurs in altered dolomite. Associated minerals include talc, chlorite, serpentine and calcite.[3] In addition to the type locality in Italy it has been reported from Kinshasa, Katanga;[3] the Chelyabinsk Oblast of the southern Urals and the Turii alkaline Massif of the Kola Peninsula in Russia; the Zirabulak Mountains of Uzbekistan; and the Goldstrike Mine of Eureka County, Nevada, US.[1]