carbon steel
economical material, nickel or chrome-plated, also gold-plated or not plated but oiled
chrome steel
Stainless, for High-Quality Instruments, no nickel-allergy
chrome/nickel steel
Stainless, antimagnetic (18/10), not hard, very popular in Electronic and Laboratory
titanium
Stainless, non-magnetic, contamination-free, very heat and chemical resistant, smooth, non-expensive
brass
non-magnetic, smooth
fine ceramic
hard and wear-ristant, heat resistant, contamination-free, chemical resistant, may break