Barstowite
Barstowite, formula Pb4[Cl6|CO3]•H2O, is a transparent to white mineral in the monoclinic system.[2] It has a Mohs hardness of 3, a white streak and an adamantine lustre.[2]
The type locality for Barstowite is Bounds Cliff, St Endellion, Cornwall in the United Kingdom.[2] It is named after Richard W. Barstow[2] (1947–1982), a Cornish mineral collector.[3]