Both Surgical Steel and Titanium are basically "silver colored" but are nowadays available in several different colors.
Zirconline® is gold colored jewelry, they are not "colored" in the classic sense, it is 316L Steel or Titanium that is covered with a thin plasma film (PVD coating). The thin film is very strong and does not fade. The technology has been used since the late 80's and is used, among other things, for orthopedic implants to provide an extra durable surface.
Zirconline® looks like real Gold, and is incredibly popular in our webshop.
What is PVD Coating? (Physical Vapour Deposition)
The jewelry is coated in a heated chamber under high vacuum. Electric voltage applied will form a plasma in the chamber andthe introduction of various gases produces an ion bombardment. This bombardment atomizes the cathode material (24k real Gold) into tiny substances which are deposited on the jewelry. The result is a hardened layer, which is biocompatible. It can be autoclaved.