How does titanium stack up against gold in jewelry?

As with steel, there are many different titanium alloy combinations, and not all are safe or suitable for body piercing application. All Wildcat titanium jewellery is Grade 23 (Ti 6AL 4V ELI) - one of only three titanium alloys recognized by the American Society for Testing of Materials (ASTM). An "F" prefix granted by the ASTM (F-136) indicates FDA consent for use in medical devices - NO HIGHER QUALIFICATION CURRENTLY EXISTS. The oxide film on Grade 23 titanium is almost three times thicker than that of Grade 1 titanium. This film acts as a barrier to prevent the release of alloying elements, and makes the jewellery resistant to corrosion. Wildcat applies a chemical etch to all G23Ti items which enhances and extends the life of anodized colours. This formula is the oxide of titanium and is safe for body implantation. Because titanium has a high affinity for oxygen, the surface oxide film heals itself instantly if it is damaged. Gold is a combination of metals added to the gold, these metals can be reactive with the body depending on the percentage of content. Example 24kt gold is almost pure with little or no other alloys, where as 14kt gold is 14/24ths gold, the other 10% is filler alloys. So the question is what are the alloys used in the gold and how do you get gold that has neutral alloys ( non-reactive to the body ). For that you will need to talk to a gold smith to get gold that has low or neutral filler content.