PHOSGENITE: Monte Poni, Sardinia (1.5)
Massive material can be cut into interesting cabochons of various colors, up to the size of the rough (several inches). Phosgenite is too soft to wear. The strong fluorescence is of interest to specialists in fluorescent minerals.
Phosgenite Value
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Phosgenite Information
| Data | Value |
| Name | Phosgenite |
| Crystallography | Tetragonal; Crystals prismatic, thick and tabular; massive, granular. |
| Colors | Colorless, white, yellowish white, gray, shades of brown, greenish, pinkish. |
| Luster | Adamantine. |
| Hardness | 2-3. |
| Density | 6.13. |
| Birefringence | 0.028. |
| Cleavage | Distinct 1 direction. Fracture conchodial. Somewhat sectile. |
| Stone Sizes | Phosgenite is very rare as a faceted gem, almost always less than 2 carats, and usually yellowish brown in color (Sardinia). A few larger stones, up to about 10 carats, are known. |
| Luminescence | Strong yellowish fluorescence in UV and X-rays. |
| Formula | Pb2CO3Cl2. |
| Pleochroism | Very weak, reddish/ greenish, only in thick pieces. |
Optics: o= 2.114-2.118; e = 2.140-2.145.
Uniaxial (+).
Occurrence: A secondary mineral in lead ore deposits.
California; Colorado; Arizona; New Mexico; Massachusetts.
Matlocks, England; Tarnow, Poland; USSR; Tasmania;
Australia; Tunisia.
Monte Poni, Sardinia: fine yellow-brown crystals up to 5 inches across; some have facetable areas.
Tsumeb, Namibia: some cuttable.
Comments: Massive material can be cut into interesting cabochons of various colors, up to the size of the rough (several inches). Phosgenite is too soft to wear. The strong fluorescence is of interest to specialists in fluorescent minerals.
Name: From phosgene, a name for the compound COCI2 (carbonyl chloride) because the mineral contains C, O, and Cl.
