As beautiful as a diamond, a faceted cerussite actually has higher dispersion and usually excellent transparency, colorless or light body color, and an adamantine luster. However, this gem is notoriously difficult to cut and too soft for jewelry use.
Although there’s an abundance of cerussite rough available, few faceters have the knowledge and ability to successfully fashion a gem from this material. Cutting cerussite is a major chore, and cutting a large one without breaking it is almost impossible. Time, patience, skill, and tender loving care are essential. Consequently, faceted cerussites number among the rarest of gems. The price of a cut stone will largely reflect the cutting cost and the size of the gem.
An important lead ore, cerussite belongs to the aragonite mineral group, which includes aragonite, strontianite, and witherite. Like its fellow group members, cerussite is a collector’s gemstone. Its hardness of 3-3.5, very brittle tenacity, and distinct cleavage make it difficult to cut and risky to wear as jewelry. In addition, it has exceptional heat sensitivity.
While faceted cerussites can make beautiful rarities, natural crystals can also make stunning specimens. They typically form in prismatic and tabular structures as well as intergrown twinned shapes, such as hearts. “Snowflakes” — masses of delicate, reticulated, thin crystals — are highly prized. Cerussites can occur in many other unusual, visually interesting shapes as well.
Yellow and green cerussites are sometimes called “chromian” or “chrome cerussites” because their color is due supposedly to the presence of chromium (Cr). However, research has shown that Cr is likely not the exclusive cause of these colors. Other contributing factors may include natural irradiation, organic staining, and inclusions.
Cerussite’s combination of high dispersion, high specific gravity (SG), low hardness, and colorless to light colors will usually distinguish it from other more commonly faceted gemstones. However, two other rarely faceted collector’s gemstones have a comparable range of colors, hardness, and SG, as well as “over the limit” (OTL) refractive indices. Like cerussite, anglesite and phosgenite can be colorless as well as white, grayish, yellowish, or greenish. Their fluorescence under ultraviolet light (UV) can also appear yellowish. (Furthermore, these minerals can crystallize in close association).
Comparison of Selected Physical and Optical Properties of Anglesite, Cerussite, and Phosgenite
Fluorescence in UV
a = 1.877; b = 1.883; γ = 1.894
Can be yellow in LW. Pale blue/green in SW.
a = 1.804; b = 2.076; γ = 2.079
o = 2.114-2.118; e = 2.140-2.145
An optic character reading can help distinguish cerussites from these other gems, and cerussite’s dispersion exceeds theirs as well.
Many localities produce cerussite, but the principal source of gem-quality material is Tsumeb, Namibia, which yields colorless, gray, and yellowish crystals, completely transparent, in masses up to several pounds.
The Touissit Mine near Oujda, Morocco is another important source of cerussite gemstones.
As if the physical properties of cerussite weren’t challenging enough, gem cutters should take precautions when working with cerussite since it contains lead. Wearing a respirator can prevent accidental ingestion or inhalation of dust particles. Using gloves or a glovebox will make cleanup much easier and safer. For more information on lead hazards and safety precautions, consult our article on toxic gems and safety tips.
Cerussite jewelry use isn’t advisable. It’s simply too fragile for anything except (very) occasional wear.