Bayldonite (BAIL-done-ite) is a rare secondary mineral with the chemical formula PbCu₃(AsO₄)₂(OH)₂. It was first discovered in Penberthy Croft Mine,

Cornwall Cornwall (; kw, Kernow ) is a historic county and ceremonial county in South West England. It is recognised as one of the Celtic nations, and is the homeland of the Cornish people. Cornwall is bordered to the north and west by the Atlantic ...

, England, United Kingdom. It is named after its discoverer, John Bayldon (1837(8) – 1872). Specimens are also found in

Tsumeb , nickname = , settlement_type = City , motto = ''Glück Auf'' (German language, German for ''Good luck'') , image_skyline = Welcome to tsumeb.jpg , imagesize = , image_caption ...

Namibia Namibia (, ), officially the Republic of Namibia, is a country in Southern Africa. Its western border is the Atlantic Ocean. It shares land borders with Zambia and Angola to the north, Botswana to the east and South Africa to the south and ea ...

, and

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

. It is sometimes used as a

gemstone A gemstone (also called a fine gem, jewel, precious stone, or semiprecious stone) is a piece of mineral crystal which, in cut and polished form, is used to make jewelry or other adornments. However, certain rocks (such as lapis lazuli, opal, ...

.Gemstones: Properties, Identification and Use By Arthur Thomas, p.159

References

Arsenate minerals Copper minerals Gemstones Monoclinic minerals Minerals in space group 15 {{mineral-stub