Laurionite Comments: Colorless, stellate spray of acicular Laurionite crystals on matrix. Location: Laurium, Greece. Copyright: © Lou Perloff / Photo Atlas of Minerals

Chemical Formula: PbCl(OH)
Locality: Ancient lead slags at Laurium, Greece.
Name Origin: Named after its locality.

Laurionite (PbCl(OH)) is a lead halide mineral. It forms colorless to white crystals in the orthorhombic crystal system and is dimorphous with paralaurionite, both members of the matlockite group.

It was first described in 1887 for an occurrence in the Laurium District, Attica, Greece and named after the town Laurium. It occurs as an oxidation product in lead ore deposits, and is also produced on lead-bearing slag by reaction with saline solutions. It occurs associated with paralaurionite, penfieldite, fiedlerite, phosgenite, cerussite and anglesite.


Discovery date : 1887
Town of Origin : LAURION, ATTIQUE
Country of Origin : GRECE

Optical properties

Optical and misc. Properties : Transparent.
Refractive Index: from 2,07 to 2,15
Axial angle 2V: LARGE

Physical Properties

Cleavage: {010} Distinct
Color: Colorless, White.
Density: 6.24
Diaphaneity: Transparent.
Hardness: 2.5-3 – Finger Nail-Calcite
Luster: Adamantine – Pearly
Streak: white


Laurionite Juliushutte, Harz Mountains, Germany Size: 2 x 2 x 1.5 cm – Thumbnail  ©  Dakota Matrix Minerals, Inc.
Origin: Laurium, Greece Owner: Lou Perloff Microscopic image
Thorikos Bay slag locality, Thorikos area, Lavrion District slag localities, Lavrion District (Laurion; Laurium), Attikí Prefecture (Attica; Attika), Greece © Elmar Lackner