History of Noble Metals. Part Two: Spanish Doubloon.

This coin has a rich history indeed. It was used as official currency in the period between the beginning of 16th and the middle of 19th century in Spain, and all of it’s colonies. Given the fact that it was made almost out of pure gold, it had a real value in countries where it wasn’t even a legal tender.
Today, it is most readily associated with pirates that sailed and plundered trading ships off the coasts of both Americas and west Europe. Since it was a Spanish coin, it often found its way into treasure booty of English pirate buccaneers. 
I will give an example here  how salvage divers, led by underwater explorer Barry Clifford - recovered 4,131 pieces of eight, and undisclosed amount of doubloons in the wreck of “Black Sam” Bellamy’s pirate galley Whydah, just off the shore of Cape Cod. It is interesting also to mention that Whydah was originally built to sail as a heavily-armed trading and transport ship for use in the Atlantic slave trade. It was supposed to carry goods from England to Africa and trade them for slaves, then sail to Caribbean to trade slaves for precious metals, medical ingredients, sugar and indigo, and finally ,sail back to England with all this cargo on board. 
At the time, slave trader Whydah was navigating somewhere between island of Cuba and Hispaniola, when Black Sam first spotted it. There was a 3 day long chase, in which Bellamy's 2 ships, (a 26 cannon galley named Sultana and 10 gun converted sloop Marianne), finally caught up to the Whydah and made it's captain surrender it without resistance. Sam Bellamy short after made Whydah his flagship - and it remained so all the way to the end of his pirate escapades.

Life sized replica of the pirate ship "Whydah".

Based on salvaged clothes and gear - look of the pirate sailors on board Whydah.

One doubloon had a worth of 16 pieces of eight at the time when Whydah sank in 1717.
Doubloon was minted and stamped into a coin from 22 karat - almost pure - gold, and hence it was ordinarily referred to as a “gold piece”.

Spanish gold doubloon.

It draws it’s name from Spanish word doblón, meaning "double" - it was worth 2 pistole, which was worth 2 escudo. One escudo was worth 16 reale, and 8 reale was also called a dollar, peso, or duro.
Most coins of that era were circular, but, initially they were hand stamped and therefore irregular in shape. The weight of the gold in coin is what mattered the most. If they weighed too much after the minting, small bits were cut off around the edges to make them roughly, (in case of the doubloon), 6.77 grams, or 0.218 ounces heavy.