Meionite

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Meionite
Meionite-Quartz-53866.jpg
Meionite (scapolite) crystals (cross-shaped) in a quartz matrix, 7.2 x 4.0 x 3.0 cm. Worcester County, Massachusetts.
General
Category Tectosilicate < br/>Scapolite group
Formula
(repeating unit)
Ca4Al6Si6O24CO3
Strunz classification 09.FB.15
Crystal symmetry Tetragonal 4/m - Dipyramidal
Unit cell a = 12.179(1)Å, c = 7.571(1)Å
Identification
Color Colorless, white, grey, pink, violet, blue, yellow, orange-brown, brown
Crystal system Tetragonal
Cleavage Distinct/good on {100}{110}
Fracture Irregular/uneven, conchoidal
Tenacity Brittle
Mohs scale hardness 5 - 6
Luster Vitreous, resinous, pearly
Streak White
Diaphaneity Transparent, opaque
Specific gravity 2.74 - 2.78
References [1][2][3]

Meionite is a tectosilicate belonging to the scapolite group with the formula Ca4Al6Si6O24CO3. Some samples may also contain a sulfate group. It was first discovered in 1801 on Mt Somma, Vesuvius, Italy.

References[edit]