Meionite
| Meionite | |
|---|---|
| 
 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
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