Location:

Settlingstones Mine, North Pennine Orefield

Settlingstones Mine lies to the north of the main North Pennine Orefield and was a major producer of witherite during the late nineteenth to early twentieth centuries. Sulphide-bearing baryte and witherite veins are hosted within limestone, sandstone and quartz dolerite (the Whin Sill). Locally, the ores are nickel-rich.

Major Minerals:

Galena, sphalerite, niccolite, ullmannite

Minor Minerals:

Pyrite, marcasite

Trace Minerals:

Include chalcopyrite, skutterudite, gersdorffite, rammelsbergite, bravoite, vaesite, violarite and millerite

Textures:

Sphalerite forms cores to radiating niccolite, itself with rims of euhedral to subhedral ullmannite and galena. Sphalerite and galena are intergrown and enclose minor amounts of pyrite, bravoite, marcasite and chalcopyrite. Niccolite has altered along grain boundaries and fractures to rammelsbergite and to fine intergrowths of vaesite, violarite and millerite

References:

Russell, 1927; Ixer, 1986