Phosgenite
Phosgenite is a very rare gem that is very soft and fluoresces yellow under long wave UV light. The chemical formula of Phosgenite is Pb2(CO)3Cl2 and its molecular weight is 545.31 gm. Phosgenite has a specific gravity of 6.12 – 6.15 (g/cm3) and the refractive index of 2.118 – 2.145 Uniaxial ( + ). It is very attractive in several colors and has a high refractive index. Facetable crystals are only found in a couple locations; Sardinia, Italy and Tsumeb, Namibia.
| Category: | Carbonate minerals |
| Chemical Formula: | Pb2(CO)3Cl2 |
| Molecular Weight: | 545.31 gm |
| Crystallography: | Tetragonal – Ditetragonal Dipyramidal |
| Crystal Habit: | Crystals are short prismatic; rarely thick tabular; commonly terminated to 30 cm; granular, massive. |
| Twinning: | None |
| Cleavage: | [110] Good, [001] Good, [010] Indistinct |
| Fracture: | Conchoidal |
| Tenacity: | Sectile, Flexible – Curved shavings or scrapings |
| Moh’s Hardness: | 2.0 – 3.0 (varying direction) |
| Density: | 6.12 – 6.15 (g/cm3) |
| Luminescence: | Weakly Fluorescent; may fluoresce Yellow under LW & SW UV, X-rays and cathode rays |
| Radioactivity: | Not Radioactive |
| Other: | Decomposes slowly in cold water, which extracts lead chloride. |
| Health Warning: | CAUTION: Contains Lead. Wash hands after handling. Do not lick or ingest; do not inhale dust when breaking. Do not grind dry. |
| Color: | Pale yellow to yellowish brown, pale brown, smoky brown, smoky violet; colorless, pale rose, grey, yellowish grey, pale green |
| Transparency: | Transparent to Translucent |
| Luster: | Adamantine |
| Refractive Index: | 2.118 – 2.145 Uniaxial ( + ) |
| Birefringence: | 0.0270 |
| Dispersion: | None |
| Pleochroism: | Very weakly pleochroic; O = reddish pink and E = pale green in thick sections |
