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.
About cerussite’s extreme sensitivity to thermal shock, Joel Arem writes: “This property became painfully evident when a 300+ carat, flawless, emerald-cut cerussite I was having cut finished out as a perfect gem — and instantly developed a thin, vertical cleavage crack across the middle of the entire stone, just because of the temperature change of removing the gem from the dop!” Cerussite, 10.62 cts, Tsumeb, Namibia. © Joel E. Arem, PhD, FGA. Used with permission.
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.
Cat’s Eye Cerussite
Very rarely, cabbed cerussites may show a chatoyant “cat’s eye” effect.
Medium yellow-green cerussite cat’s eye, 3.19 cts, 6.4 x 4 mm, oval cabochon. (Unknown origin, possibly Namibia). © The Gem Trader. Used with permission.
What is Chrome Cerussite?
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.
Not all cerussites have an adamantine luster. Other possibilities include submetallic, vitreous, pearly, and resinous.
A cluster of cerussite crystals with resinous (almost greasy) luster, 2.5 x 1.5 x 1 cm, Kapi Mine, Dundas, Tasmania, Australia. Photo courtesy of liveauctioneers.com and Jasper52.
Faceted cerussites may show birefringent effects, such as facet doubling, but not pleochroism.
Cerussites may fluoresce pale blue or green in shortwave ultraviolet light (UV) and pinkish orange or yellow shades in longwave UV.
This crystal specimen features a cerussite on a plate of calcites. Under UV light, the cerussite fluoresces blue and the calcite orange. 8.0 x 7.0 x 4.0 cm (cerussite 3 cm), Tsumeb Mine, Tsumeb, Otjikoto Region, Namibia. © Rob Lavinsky, www.iRocks.com. Used with permission.
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.
This anglesite specimen is a pseudomorph after cerussite. Although the specimen has kept the external complex crystal structure of a cerussite, its chemical formula has become that of anglesite. 7.0 x 6.0 x 3.5 cm, Central Mine, Broken Hill, New South Wales, Australia. © Rob Lavinsky, www.iRocks.com. Used with permission.
Before the health hazards of lead were well known, cerussite was used to create paints and cosmetics. People have utilized natural as well as synthetic forms of this mineral for these purposes since ancient times.
Currently, scientists create synthetic cerussite crystals for a variety of research purposes. However, there’s no known jewelry use for this lab-created material.
No known gemstone treatments or enhancements.
Cerussite, 32.87 cts, Tsumeb, Namibia. Photo © Joel E. Arem, PhD, FGA. Used with permission.
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.
Other notable sources include the following localities:
- United States: Tiger, Arizona; California; Colorado; Idaho; Montana; Nevada; New Mexico; South Dakota; Utah.
- Australia: Broken Hill Mine, Broken Hill, New South Wales; Dundas, Tasmania.
- China; Czech Republic; Germany; Iran; Monte Poni, Sardinia, Italy; Republic of the Congo; Slovakia; Spain; Leadhills, Scotland, United Kingdom; Zambia.
Cerussites, 4.2 x 3.4 x 1.4 cm, Daoping Mine, Gongcheng Co., Guilin Prefecture, Guangxi Zhuang A.R., China. © Rob Lavinsky, www.iRocks.com. Used with permission.
Large masses of transparent rough from Tsumeb, Namibia could cut stones of several thousand carats. (However, the cohesion of these large stones poses a significant challenge to any cutting).
Cat’s eyes from Tiger, Arizona and Tsumeb, Namibia can range from 2 to 6 carats.
The “Light of the Desert,” the world’s largest faceted cerussite, weighs 898 carats. It hails from Namibia and resides in the Royal Ontario Museum in Toronto, Canada.
- Smithsonian Institution (Washington, DC): 4.7 (pale yellow, Tsumeb, Namibia); 109.9 (smoky, Tsumeb, Namibia).
- National Museums of Canada (Ottawa, Ontario): 71.25 (colorless octagon, Tsumeb, Namibia).
- Private Collection: 408 (brownish gray oval, Tsumeb, Namibia); 262 (colorless emerald cut, Tsumeb, Namibia).
Pear-cut cerussite, 120.22 cts. © Joel E. Arem, PhD, FGA. Used with permission.
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.
Faceted cerussites, 4.1 and 5.3 cts, Tsumeb, Namibia. © Joel E. Arem, PhD, FGA. Used with permission.