Pachnolite

Formula: NaCaAlF₆.H₂O

Origin of name: from Greek for frost

Crystal system: monoclinic

Crystal class: 2/m

Twinning: universal on {100}

Unit cell: a = 12.14 Å, b = 10.41 Å, c = 15.72 Å, b = 90.3°

Colour: colourless to white

Diaphaneity: transparent to translucent

Luster: vitreous

Habit: crystals slender prismatic, elongated on c-axis, striated, massive, cleavable to granular or chalcedony-like

Hardness: 3

Specific gravity: 2.983

Cleavage: 1; {001} indistinct

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: dimorphous with thomsenolite