Chemical composition -- Lead carbonate
Color -- Colorless, gray, yellowish.
Optics -- R.I 1.80-2.08. Dispersion 0.055 (very high).
Durability -- Hardness 3-3.5. Very brittle.
Crystal structure -- Orthorhombic.
Specific Gravity -- 6.55 (very dense).
Sources -- Many widely scattered locales, the best being Tsumeb in Namibia. Cerussite makes extremely brilliant and beautiful faceted stones, but cutting is extremely difficult due to the softness, brittleness, and heat sensitivity. Consequently, finished stones are very rare collector's items, even though rough material is abundant.