Cerussite (also known as lead carbonate or white lead ore) is a
mineral consisting of
lead carbonate
Lead(II) carbonate is the chemical compound with the chemical formula . It is a white solid with several practical uses, despite its toxicity. It occurs naturally as the mineral cerussite.
Structure
Like all metal carbonates, lead(II) carbonate a ...
(PbCO
3), and is an important
ore
Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit.Encyclopædia Britannica. "Ore". Encyclopædia Britannica Online. Retrieved 7 April ...
of lead. The name is from the
Latin ''cerussa'',
white lead
White lead is the basic lead carbonate 2PbCO3·Pb(OH)2. It is a complex salt, containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite. It was ...
. ''Cerussa nativa'' was mentioned by
Conrad Gessner in 1565, and in 1832
F. S. Beudant applied the name ''céruse'' to the mineral, whilst the present form, cerussite, is due to
W. Haidinger
Wilhelm Karl Ritter von Haidinger (or Wilhelm von Haidinger, or most often Wilhelm Haidinger) (5 February 179519 March 1871) was an Austrian mineralogist.
Early life
Haidinger's father was the mineralogist Karl Haidinger (1756–1797), who died w ...
(1845). Miners' names in early use were lead-spar and white-lead-ore.
Cerussite
crystallizes in the
orthorhombic crystal system and is isomorphous with
aragonite
Aragonite is a carbonate mineral, one of the three most common naturally occurring crystal forms of calcium carbonate, (the other forms being the minerals calcite and vaterite). It is formed by biological and physical processes, including pr ...
. Like aragonite it is very frequently
twinned, the compound crystals being pseudo-hexagonal in form. Three crystals are usually twinned together on two faces of the prism, producing six-rayed stellate groups with the individual crystals intercrossing at angles of nearly 60°. Crystals are of frequent occurrence and they usually have very bright and smooth faces. The mineral also occurs in compact granular masses, and sometimes in fibrous forms. The mineral is usually colorless or white, sometimes grey or greenish in tint and varies from transparent to translucent with an adamantine lustre. It is very brittle, and has a
conchoidal fracture
Conchoidal fracture describes the way that brittle materials break or fracture when they do not follow any natural planes of separation. Mindat.org defines conchoidal fracture as follows: "a fracture with smooth, curved surfaces, typically sligh ...
. It has a
Mohs hardness
The Mohs scale of mineral hardness () is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of various minerals through the ability of harder material to scratch softer material.
The scale was introduced in 1812 by ...
of 3 to 3.75 and a
specific gravity of 6.5. A variety containing 7% of zinc carbonate, replacing lead carbonate, is known as iglesiasite, from Iglesias in
Sardinia, where it is found.
The mineral may be readily recognized by its characteristic twinning, in conjunction with the adamantine lustre and high specific gravity. It dissolves with effervescence in dilute
nitric acid. A
blowpipe test will cause it to fuse very readily, and gives indications for lead.
Finely crystallized specimens have been obtained from the
Friedrichssegen mine in
Lahnstein in
Rhineland-Palatinate,
Johanngeorgenstadt
Johanngeorgenstadt () is a mining town in Saxony’s Ore Mountains, 17 km south of Aue, and 27 km northwest of Karlovy Vary. It lies in the district of Erzgebirgskreis, on the border with the Czech Republic, is a state-recognized healt ...
in
Saxony,
Stříbro in the
Czech Republic,
Phoenixville
Phoenixville is a borough in Chester County, Pennsylvania, United States. It is located northwest of Philadelphia at the junction of French Creek and the Schuylkill River. It is in the Philadelphia metropolitan area. The population is 18,616 ...
in
Pennsylvania,
Broken Hill in New South Wales, and several other localities. Delicate
acicular crystals of considerable length were found long ago in the Pentire Glaze mine near
St Minver
St Minver ( kw, Sen Menvra) is the name of an ecclesiastical parish, a civil parish and a village in north Cornwall, England, United Kingdom.
The civil parish of St Minver is in Bodmin Registration District and is nominally divided into St Minv ...
in
Cornwall. Cerussite is often found in considerable quantities, and has a lead content of up to 77.5%.
Lead(II) carbonate is practically insoluble in neutral water (solubility product
b2+CO
32−] ≈ 1.5×10
−13 at 25 °C), but will dissolve in dilute acids.
Commercial uses
"
White lead
White lead is the basic lead carbonate 2PbCO3·Pb(OH)2. It is a complex salt, containing both carbonate and hydroxide ions. White lead occurs naturally as a mineral, in which context it is known as hydrocerussite, a hydrate of cerussite. It was ...
" is the key ingredient in (now discontinued)
lead paints. Ingestion of lead-based paint chips is the most common cause of
lead poisoning
Lead poisoning, also known as plumbism and saturnism, is a type of metal poisoning caused by lead in the body. The brain is the most sensitive. Symptoms may include abdominal pain, constipation, headaches, irritability, memory problems, infertil ...
in children.
Both "white lead" and
lead acetate Lead acetate can refer to:
* Lead subacetate (Basic lead acetate), Pb3(OH)4(CH3COO)2
* Lead(IV) acetate (plumbic acetate), Pb(CH3COO)4
* Lead(II) acetate
Lead(II) acetate (Pb(CH3COO)2), also known as lead acetate, lead diacetate, plumbous acetate ...
have been used in cosmetics throughout history, though this practice has ceased in Western countries.
Cerussite images
File:cerussite09.jpg, Crystals of cerussite, a secondary lead ore
File:Light of the Desert.jpg, At 890 carats, the Light of the Desert (located at Toronto's Royal Ontario Museum) is the world's largest faceted cerussite.
See also
*
Venetian ceruse – Cerussite-based cosmetic popularly thought to be worn by
Elizabeth I of England
References
*
{{Reflist
External links
Mineral galleries
Carbonate minerals
Gemstones
Lead minerals
Luminescent minerals
Minerals in space group 62
Orthorhombic minerals
Aragonite group