A low furnace in which rich lead ore is reduced.

plural of ore hearth

alquifou

olivenite

A variety of bournonite with wheel-shaped twin crystals.

limonite

aikinite

(mineralogy) A variety of jamesonite, sometimes found in capillary forms and like a cobweb, but also massive.

argillaceous oxide of iron, occurring in round grains the size of peas; pisolitic ore

(graph theory) A theorem that considers the sum of the degrees of pairs of non-adjacent vertices: if every such pair has a sum that at least equals the total number of vertices in the graph, then the graph is Hamiltonian.