Halite

General

 

Category: Halide mineral

 

Formula: NaCl

 

IMA symbol: Hl

 

Strunz classification: 3.AA.20

 

Crystal system: Cubic

 

Crystal class: Hexoctahedral (m3m) H-M symbol: (4/m 3 2/m)

 

Space group: Fm3m

 

Unit cell: a = 5.6404(1) Å; Z = 4

 

 

Identification

 

Formula mass: 58.433 g/mol

 

Color: Colorless or white when pure. Impurities produce any color but usually yellow, gray, black, brown, red

 

Crystal habit: Predominantly cubes and in massive sedimentary beds, but also granular, fibrous and compact

 

Cleavage: Perfect {001}, three directions cubic

 

Fracture: Conchoidal

 

Tenacity: Brittle

 

Mohs scale hardness: 2.0–2.5

 

Luster: Vitreous

 

Streak: White

 

Diaphaneity: Transparent to Translucent

 

Specific gravity: 2.17

 

Optical properties: Isotropic

 

Refractive index: n = 1.544

 

Melting point: 800.7°C

 

Solubility: Water-soluble

 

Other characteristics: Salty flavor, fluorescent

 

 

Done