Barstowite, formula Pb₄ CO₃��H₂O, is a transparent to white mineral in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

system.Barstowite at Mindat.org mineralogical website
/ref> It has a

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 3, a white streak and an adamantine lustre. The type locality for Barstowite is Bounds Cliff,

St Endellion St Endellion () is a civil parishes in England, civil parish and hamlet in north Cornwall, England, United Kingdom. The hamlet and parish church are situated four miles (6.5 km) north of Wadebridge. The parish takes its name from Saint Ende ...

Cornwall Cornwall (; or ) is a Ceremonial counties of England, ceremonial county in South West England. It is also one of the Celtic nations and the homeland of the Cornish people. The county is bordered by the Atlantic Ocean to the north and west, ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

. It is named after Richard W. Barstow (1947–1982), a Cornish mineral collector.

References

Lead minerals Carbonate minerals Chloride minerals Monoclinic minerals Minerals in space group 11 {{carbonate-mineral-stub