Phosgenite is a lead chlorocarbonate mineral that was named in 1820 by August Breithaupt because it has phosgene as a component. Fine mineral specimens and facet grade material are rare. The mineral is from the tetragonal crystal system and specimens are typically prismatic or tabular in form. Crystals have vertical striations and might have pointed terminations. Occasionally specimens will have a helical twist around the principal axis. Specimens from the Monteponi Mine, Sardinia, Italy are greatly prized.

General Information

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

Common Name

Phosgenite

Transparency

Translucent-Transparent

Dispersion

Strength: Strong Fire

Refractive Index

2.117-2.145

Birefringence

0.026- 0.028

Optic Character

Uniaxial

Optic Sign

Positive

Polariscope Reaction

Doubly Refractive (DR)

Fluorescence

SWUV: Strong yellow with yellow phosphorescence or orange
LWUV: Yellow

Pleochroism

Dichroic, Weak red and green

Hardness

2-3

Streak

White

Specific Gravity

6.12-6.15

Toughness

Poor

Luster

Adamantine, Greasy

Fracture

Conchoidal

Cleavage

Perfect

Chemical Name

Lead Carbonate Chloride

Chemical Formula

Pb₂CO₃Cl₂

Crystal System

Tetragonal

Chemistry Classification

Carbonate

null Colors

Brown
Colorless
Gray
Green
Pink
White
Yellow

Alternate Names

Cromfordite, Horn Lead, Corneous Lead

Countries of Origin

Greece; Russian Federation; Morocco; Namibia; United States of America; Poland; Italy; Australia; United Kingdom of Great Britain and Northern Ireland

History

Phosgenite was first found at the lead mine at Cromford, Derbyshire, England in 1800.

Care

Very soft gentle care, not suitable for jewelry. Soluble in acid. This stone contains lead and special care needs to be used. Always wash your hands after handling and do not ingest. Cut stones using a liquid medium and use a mask so not to inhale dust.