gypsum and iron ore and limestone Minerals, gemstones, crystals, elements Diamond, carbon Quartz, granite Sandstone

Brass is an alloy of copper and zinc, in proportions which can be varied to achieve varying mechanical and electrical properties.[1] It is a substitutional alloy: atoms of the two constituents may replace each other within the same crystal structure.

Bronze is an alloy also containing copper, but instead of zinc it has tin;[2] both bronze and brass may include small proportions of a range of other elements including arsenic, lead, phosphorus, aluminum, manganese, and silicon. The distinction between the two alloys is largely historical,[3] and modern practice in museums and archaeology increasingly avoids both terms for historical objects in favour of the all-embracing “copper alloy”.[4]