On Sunday, August 7th during the preliminaries for the 100m women’s backstroke, American swimmer (silver medalist) Kathleen Baker lost one of her signature pearl earrings to Rio’s Olympic pool, the depths of which reach almost ten feet. Thankfully, a diver went down to search for the earrings, and ultimately recovered it from Baker’s lane around the 15 meter mark.
The story has a happy ending, but it does bring up a few cautions for anyone who wears their jewelry swimming or who may be thinking of adopting some good luck swimming pearls of their own.
The most obvious thing to consider is that jewelry can and will fall off. Earrings, necklaces, bracelets, and rings all have ways of finding themselves falling to the bottom of pools, lakes, rivers, and oceans all over the world. If you're lucky you will find them again, but more often the pieces are gone for good.
Now you may say "but I can lose my jewelry on dry land as well!" I would agree with you, but there is a less obvious but possibly even more serious concern when it comes to swimming in jewelry.
Both natural and cultured pearls are covered in a luminous substance called nacre. In natural pearls this layer has built up over an immense amount of time and is incredibly thick (hence their high cost and relative rarity), in the more common cultured pearl the nacre present on the surface of the seed material (see image). The nacre contains some organic proteins and also calcium carbonate. Calcium carbonate dissolves when it comes into contact with acid. Even mild acids (perfumes, lotions, hairspray, and makeup) can weaken the structure of the pearl’s nacre and eventually dissolve its beautiful shine.
The chlorine used to purify water is actually sodium hypochlorite, the same stuff you find in household bleach. This particular type of chlorine is highly oxidizing, and has a tendency to destroy a pearl’s luster on contact. Over time the pearl's nacre will come off, leaving a cloudy surface; it may even peal off in layers while the inside continues to disintegrate (it's not pretty, trust me).
So while all that is happening to your pearls, your metal is going through an equal amount of hardship. Chlorine can react with precious metals, including gold and silver. If you’re in the pool every day or cleaning with bleach products it can cause pits in the gold’s surface that look like little dents. Chlorine can actually break down gold jewelry to the point of disintegration. A gold ring, placed in undiluted bleach, can disintegrate within minutes of exposure. Stress corrosion cracking can also occur in any weak joints of the jewelry or areas where it has been repaired. In general, platinum doesn’t react with chlorinated pool water, but some platinum rings contain gold solder that can.
But I have to wear it!
If you absolutely must wear jewelry in the pool then the best metallic material to wear is stainless steel, specifically type 316 stainless steel, which is resistant to chloride attacks from sweat and sea water. Titanium alloys also stand up well. If you are firmly on board the pearls-in-the-pool train then I suggest imitation pearls. There are various types of imitation pearls from plastic, to glass, or shell. The relative inexpensive nature of the imitations means your heart and your wallet wont break when an earring is lost or dissolved in the pool.
No matter what your jewelry’s made of, one thing is certain: all of that sweat and chlorine will dull its brilliance, so make sure to clean it. Most colored gems can be cleaned in warm water with mild soap and a soft brush. Precious metals should be cleaned similarly. When in doubt about cleaning jewelry make sure you ask! Gemologists are here to help.