Customers may think that faulty manufacturing or under karating might be the problem when a ring turns, blackening or discoloring either skin and clothing, or jewelry itself. However, that is not the case.

The most common reason is metallic abrasion, caused by make-up on skin or clothing. Cosmetics often contain compounds harder than the jewelry itself, that wear or rub off very tiny particles. Very finely divided metal always appears black rather than metallic, so it looks like a jet black dust. When this dust  contacts absorbent surfaces such as skin or clothing, it sticks forming a black smudge.

To prevent this, you must try switching cosmetics. If this is not possible, recommend the removal of rings and other jewelry while applying them, and clean skin areas in contact with jewelry  with soap and water.

Another cause is actual corrosion of the metals. Gold itself does not corrode, but its primary base metal alloys of silver or copper will do so - forming very dark chemical compounds - under moist or wet conditions.

When you perspire, fats and fatty acids released can cause corrosion of 14Kt. gold, especially when exposed to heat and air.This problem can be worse in costal and semitropical areas, where chlorides combine with perspiration to form a corrosice element that discolors skin. Smog fumes gradually attack jewelry and are evident as a tarnish that rubs off on the skin.

Remove jewelry often and use an absorbant powder, free of abrasives, on skin that contacts jewelry.

In addition to these corrective actions, it is recommended that you switch to 18kt. gold or platinum. The lowere base metal content of 18Kt. gold (25 percent versus almost 42 percent) significantly reduces the problem, and the use of platinum should eliminate it completely.