Tuesday, July 17, 2012

7/17/12 Report - How To Tell The Denomination of a Worn Cob

Written by the treasureguide for the exclusive use of treasurebeaches report.blogspot.com.

Here are four silver cobs, all minted in Mexico, and all from the same 1715 shipwreck beach. 

The denomination is visible on only one of the four. 

So how do you know the denomination when it is not marked on the cob?

One way that people sometimes use, is the weight of the cob.

An eight reale should weigh about 27.3 grams, a four real about 13.65 grams, a two real about 6.825 grams, a one real about 3.4 grams, a half real about 1.7 grams and a quarter real about .85 grams.

You can't always go by weight though.  Besides the fact that it appears that some cobs were not manufactured at exactly the correct weight, some cobs lost significant amounts of silver while rolling around in the salt water and sand.

Can you tell the denomination of these cobs?

Three of them are near the proper weight for their denomination.   One is way off.

From top to bottom is a 2 real, 1 real, half real and another half real.

The top one is the same two real that I showed a few days ago when I talked about the shields.

The last half real has been severely corroded and has lost nearly half of its original weight.   In addition to loss of weight, I can tell that it corroded by the loss of detail in the design.

When you can't tell by weight, you can often tell the denomination by the design of the cob, when you can see enough of it.

On the undersized cob, you can make out the cross, which is the type used by the Mexico mint. 

There are rare quarter reals that show a cross, but this is not likely one of those.  Most quarter reals show a castle on one side and a lion on the other. 

On the other side, this one shows a bit of a Carlos monogram.  That would indicate that it is an undersized Mexican half real rather than a quarter real.

To sum up the main point, when you don't see a denomination mark on a cob, and can't tell by weight, you can usually tell by any remaining design features.  That might take a lot of research in some cases.

My apologies to those of you who read this blog early in the morning.   I often have a lot of typos and errors that don't get fixed until later in the day.

There are no storms brewing.  The wind is south/southwest.  Seas are running about two feet, decreasing later today.  No change in conditions predicted.

Here is another surf web site that you might check out.


Happy hunting,