Message:

<p>[QUOTE=&quot;Colonialjohn, post: 3699340, member: 57741&quot;]I have been doing more research on these 1821 8R Zacatecas. INSIDER one of the more perplexing scenarios in this matter is we see at least 1/4 OF ALL 1821 Zacatecas 8R&#039;s in AU or higher (slabbed or not slabbed) with this discoloration or non-homogeneous surfaces. Many are considered IMPROPERLY CLEANED since a TPG observing a non-homogeneous surface can only assume its been cleaned. I came across a recent article &quot;The Environmental History of Silver in New Spain between 16th-19thC by the author Quintero from McGill University (i.e., his PhD thesis). Its complex but I will try to make it simple to understand if I am correct in my assumptions on this issue. Not all silver bearing ores in Zacatecas were silver extracted with mercury. We had light colored ores (i.e., AgCL based ores) and dark colored ores (AgS or sulfur bearing ores). The darker ores were smelted requiring sometimes litharge (i.e, Pb) and many times just charcoal since mercury did not work very well AT ALL in extracting sulfur (S) from the darker ores. My guess for 1821 this year of INDEPENDENCE the assayers may have decided to amalgamate all the ores, there may have been a lack of salt (i.e., normally brought in great distances from the coast) or copper sulfate, charcoal, or other ingredients which may not have been available in 1821 creating a poorly colored silver finish alloy? Remember there are MANY DISCOLORED NON-HOMOGENEOUS looking 1821&#039;s. My theory which can be proven is by cutting a piece in half and examining the surface to core by SEM/EDS (not XRF analysis) and then looking at the Ag compounds found in the alloy such as AgS, AgCL and Hg2CL2. I suspect the sulfur levels or high concentrations of AgS being the root cause of these issues due to not smelting the AgS ores (i.e., darker ores) and simply amalgamating the darker and lighter ores together. THe other possibility is Not having enough salt (NaCL) may also be a root cause as to properly amalgamate a silver ore it must be in the form of AgCL and NOT AgS. The salt with smelting in a furnace transforms AgS to AgCL which then the Hg binds to the CL forming mercuric chloride (Hg2CL2). Its complicated to the newbie to understand all the ingredients of the Patio Amalgamation process and the other treatment operation at these Hacienda Mints being smelting of the sulfur bearing ores. XRF will not help too much since high S readings could be argued as environmentally (i.e., atmospheric exposure) derived as with high CL levels. Actually I will be presenting these findings to a group of collectors shortly. SEM/EDS allows compounds to be quantified unlike XRF which just provides singular elements in a quantitative manner. It would be virtually verified if we see darker areas (AgS) right to the core of the coin. Any further inquires are welcome in this matter ... JPL[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in