A "biscuit" anyone? Tea provided, but please bring reinforced teeth and a cement mixer for a stomach!

[robinjojo]

I just picked up this interesting and scarce "biscuit", an Netherlands ducatoon encrusted with marine sediment, salvaged from the wreck of the Vliegenthart or “Flying Hart", an East Indiaman that ran aground in 1735 due to an unfortunate combination of a gale, spring tide and pilot error off the coast of Zeeland.  She sank, along with her sister ship the Anna Catharina with the loss of all crew and passengers.

Salvage operations were undertaken shortly afterwards, but with no success.  However, a contemporary map of the wreck led to the successful salvage between 1983-1992.

Among the chests of coins found were small ones containing ducatoons, illegal contraband under the law at that time forbidding the export of these coins from the Netherlands.

Here's the biscuit, with a cement-like covering of marine mud and fragments of shells:

 Vliegenthart (1735), "biscuit" - an encrusted Netherlands ducatoon.

48.55 grams

46mm diameter 

The contraband ducatoons are generally in very high grade and are available from time to time, mostly through auctions.  Even without a certificate, if a 1734 ducatoon is being offered, there is a very high chance that it came from the Vliegenthart.  These attractive coins are in pretty strong demand.  Additionally, the wreck has yielded thousands of 8 reales, mostly from Mexico, in varying states of preservation.

Here are two Gelderland ducatoons 1734, from the Vliegenthart.

Netherlands, Gelderland, two ducatons salvaged from the Vliegenthart (1735).

32.61 grams left and 32.49 grams right.

Edited February 10, 2023 by robinjojo

[Nerosmyfavorite68]

It's a very attractive issue. Were the two cleaned versions once like the biscuit?  It's an interesting uncleaned.

[Theodosius]

Do you plan on cleaning it?

It is interesting seeing how it came from the ocean as it is...

John 

[robinjojo]

1 hour ago, Nerosmyfavorite68 said:

It's a very attractive issue. Were the two cleaned versions once like the biscuit?  It's an interesting uncleaned.

 

1 hour ago, Theodosius said:

Do you plan on cleaning it?

It is interesting seeing how it came from the ocean as it is...

John 

I doubt that the two ducatoons were found as biscuits on the sea floor.  Usually, the nicely preserved coins come from a sizeable mass of coins, with the nicer ones towards the center and the more corroded ones towards the outer area.  For this salvage there were small chests containing the contraband coins, and apparently something like peat was packed around them.  At least that was the case for the large chests discovered.  Being in a chest and submerged in mud and sand probably helped to preserve these coins over the centuries.  

On the other hand individual coins or even two or three coins can become encrusted on the sea floor.  Since these coins have little or no protection to the salt water and oxygen, they would be quite corroded.  This  is true for silver coins.  Gold coins are not affected generally, but they can acquire a sandblasted appearance due to the copper alloy corroding and they can be encrusted with coral. That's why it is usually best to leave these encrusted coins as is, instead of trying to free them from the cement-like sediment.  Such an effort would very likely yield very disappointing results.  So, the biscuit will remain as it is.  These artifacts are actually quite scarce and collectors collect them very actively.  

Edited February 10, 2023 by robinjojo

[robinjojo]

Here are the two biscuits from the Vliegenthart  that were sold on eBay recently.  I bought the one on the right intact.  The other example is also very interesting, with the coin partially exposed.  From what I can see that coin is quite thin, very corroded I would imagine. Judging from the angular edge, the coin in the center of that concretion might be a cob, but it might be a ducatoon as well.

Close examination of the surface of the biscuit is really interesting.  It's really quite complex.  In addition to the shell fragments, there are concentrations of what appear to be silver sulfide.  This would be expected, since silver is highly reactive to salt water and oxygen, altering quickly in a chemical reaction.  Also, there are some copper oxides.  This too would be expected, with the copper alloy altering to malachite or azurite.  The copper oxides appear as very small botryoidal groups.  The silver sulfides on the other hand manifest as tiny black reflective crystals.  Very interesting indeed! 

Edited February 10, 2023 by robinjojo

[JeandAcre]

23 hours ago, robinjojo said:

 

I doubt that the two ducatoons were found as biscuits on the sea floor.  Usually, the nicely preserved coins come from a sizeable mass of coins, with the nicer ones towards the center and the more corroded ones towards the outer area.  For this salvage there were small chests containing the contraband coins, and apparently something like peat was packed around them.  At least that was the case for the large chests discovered.  Being in a chest and submerged in mud and sand probably helped to preserve these coins over the centuries.  

On the other hand individual coins or even two or three coins can become encrusted on the sea floor.  Since these coins have little or no protection to the salt water and oxygen, they would be quite corroded.  This  is true for silver coins.  Gold coins are not affected generally, but they can acquire a sandblasted appearance due to the copper alloy corroding and they can be encrusted with coral. That's why it is usually best to leave these encrusted coins as is, instead of trying to free them from the cement-like sediment.  Such an effort would very likely yield very disappointing results.  So, the biscuit will remain as it is.  These artifacts are actually quite scarce and collectors collect them very actively.  

@robinjojo, I have to agree with your broadly implicit point about cleaning these, above and beyond the question of what you'd end up with if you did. 

Right, to wallow in the obvious, in the case of a specific, well documented and correspondingly dramatic shipwreck, the encrustation becomes central to the coins' narrative.  This is where the historical significance becomes an integral part of --or at least overrules-- (conventional) esthetic factors.

(Busted: as a medievals guy, I speak this, fluently.)

Edited February 11, 2023 by JeandAcre