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Atocha Silver Bars Approximately one thousand silver bars weighing between sixty and seventy pounds were listed on the Atocha's manifest when it sank off the Florida Keys on September 6, 1622. The majority of the ingots were the property of individuals, although one hundred thirty-three bars, shipped in thirty-four boxes and marked with a red crown belonged to King Philip IV himself. Many Atocha silver bars were mined and processed in Potosi, now in present day Bolivia, and hauled great distances to Portobello, a Caribbean port in what is now the Republic of Panama. The cargo was then loaded onto the Atocha; each item registered as it was brought aboard. During processing, each bar was struck with a serial number and various monograms indicating the owner or shipper. The mint's assayer would then remove his "bite", a small piece that was tested to determine the purity of silver. Once purity was established, the ingot was struck with the "Ley" or fineness number, typically 2380 out of a possible 2400 or 99.2% pure. All bars not belonging to the king were also struck with one or more tax stamps indicating the 20% royal tax "Quinto" was collected. Some bars were dated. Each bar was graded and assigned a class factor rating ranging from .5 to 1.0. The very best bars received a 1.0 rating and are characterized as being listed on the ships manifest and having a clear fineness mark, talley number, and at least a partial date. Class factor .9 bars are similar, but usually lack a date or have weaker markings. 0.8 bars are weaker yet, are almost always undated, but can still be traced to the manifest. 0.7 bars have at least two marks, but not of sufficient quality to trace the bar to the ships manifest. 0.6 bars have only light traces of marks and .5 bars have no marks at all. Atocha
bars are supplied with the
original photo type Certificate of Authenticity and a booklet "Shipwrecks
and Their Coins: Volume 1 - 1622 Spanish Treasure Fleet" that
provides details about the fleet and its coins. |
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