Leadhillite is a lead sulfate carbonate hydroxide mineral, often associated with anglesite. It has the formula Pb4SO4(CO3)2(OH)2. Leadhillite crystallises in the monoclinic system, but develops pseudo-hexagonal forms due to crystal twinning. It forms transparent to translucent variably coloured crystals with an adamantine lustre. It is quite soft with a Mohs hardness of 2.5 and a relatively high specific gravity of 6.26 to 6.55.
The Leadhills and Wanlockhead Light Railway was a short branch railway built in Scotland to serve mining settlements, high in the Lowther Hills, connecting them to the Carlisle - Carstairs main line. The line was opened in 1901 - 1902, and was the highest standard gauge railway line in the British Isles. Hoped-for developments did not emerge, and when the world lead price slumped in the 1920s, the line sustained heavy losses. It was closed on 2 January 1939.
Leadhills, originally settled for the accommodation of miners, is a village in South Lanarkshire, Scotland, 5 3⁄4 miles (9.3 km) WSW of Elvanfoot. The population in 1901 was 835. It was originally known as Waterhead.