Secondary mineral

Secondary minerals are minerals that, unlike the primary minerals , only emerged after the rock surrounding them formed. They are formed from these through chemical weathering or metamorphosis . Deposition from hydrothermal solutions in cavities in the rock also frequently occurs . Examples of this are agates and druses . If the cavity was created by leaching out a crystal and is completely filled again with another mineral, this shows a "false", pseudomorphic crystal form.

Many secondary minerals are formed in older mining locations such as mine tunnels , roads and heaps due to weathering, in particular due to oxidation . Many of these minerals are therefore discovered for the first time in pits and named after them (examples: schools mountainite , goslarite ).

Examples of the weathering of ores are the formation of melanterite and limonite from pyrite and of chalcanthite , azurite and malachite from copper ores.