The Atlantic Ocean has given up 17 tons of colonial-era coins in what could be the richest shipwreck treasure ever. One coin expert estimated the value at $500 million or about $1,000 a coin.
But what affect will years of sea water have on the silver and gold coins recovered by Odyssey Marine Exploration of Tampa?
?Sea water is very corrosive and thus very destructive to silver coins,? said Dave Harper, editor of Numismatic News. The value of the silver coins will rest on both their original condition as raised from the bottom of the sea and the ability of the conservation process to turn the coins into pleasing looking collectibles.?
As for the gold coins, Harper said gold survives better under water so the conservation process should be easier and the collector values higher.
But collectors need to remember that this is sea-salvaged coinage, said Thomas Michael, coin market analyst for Krause Publications.
?Think of sea-salvaged coins as treasure because that is their first marketable promotional vein,? Michael said.
?Because of the effects of salt water on metal, most all sea-salvaged silver coins are in a pitted state after being recovered and cleaned. Gold coins fair better in the sea, but cleaning often hairlines them, reducing their value in the traditional numismatic market.?
But as examples of sunken treasure, the coins will likely hold a strong appeal as historical artifacts, he said.
?My standard line for sea-salvage coins is, ?There will always be more,?? said George Cuhaj, coin and paper money market analyst for Krause Publications. Advances in technology that allow for small objects to be found in deep seas or even under the sea floor will increase the number of ?lost? coins found, he said.
What does that do to the market?
?There has always been a separation between coins not lost or buried and sea-salvage or buried material,? Cuhaj said, ?especially on the silver and base metals that corrode easier.?
Depending on the marketing effort and the premium, the find ?could be good, or it could hurt the hobby,? he said.
The treasure find was announced May 18. Citing security reasons, Odyssey Exploration has not given details on the specifics of the coins recovered or the location of the find.