Zinc is a main group metal, #Z=30#...the which commonly forms #Zn^(2+)# ions … it is commonly found in the zinc-blende ore, i.e. #ZnS#... Brass is an alloy of zinc and copper, and apart from its primary use to make musical instruments, the alloy is commonly used in gas fittings, given that you CANNOT make a SPARK from hitting two pieces of brass together...why should this be a desirable property of metallic gas fittings?