Halite

Halite
Halite from the Wieliczka salt mine, Małopolskie, Poland (size: 16x15x13cm)
General
Category	Halide mineral
Formula (repeating unit)	NaCl
Strunz classification	03.AA.20
Crystal symmetry	Isometric hexoctahedral 4/m 3 2/m
Unit cell	a = 5.6404(1) Å; Z = 4
Identification
Molecular mass	58.433 g/mol
Color	Colorless or white; also blue, purple, red, pink, yellow, orange, or gray
Crystal habit	Predominantly cubes and in massive sedimentary beds, but also granular, fibrous and compact
Crystal system	Cubic
Cleavage	Perfect {001}, three directions cubic
Fracture	Conchoidal
Tenacity	Brittle
Mohs scale hardness	2 - 2.5
Luster	Vitreous
Streak	White
Diaphaneity	Transparent
Specific gravity	2.17
Optical properties	Isotropic
Refractive index	n = 1.544
Solubility	Water soluble
Other characteristics	Salty flavor, Fluorescent
References	[1][2][3]

Halite is the mineral a lot of people call "rock salt". It is a different form of sodium chloride (NaCl). It looks like it is made out of cubes.

1. ↑ http://rruff.geo.arizona.edu/doclib/hom/halite.pdf Handbook of Mineralogy
2. ↑ Mindat.org
3. ↑ Webmineral data