Only an obverse?

I'm not sure about this on some foreign coins , on our American coins the reeded edge is added during the stricking process. the retaining collar acts as a third die and has the reeding on it. when the coins metal is pushed against the collar this add the reeding.

 

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It is not my scale (balance rather) per say. I work at one of the worlds largest copper metallurgy technology develoment facilities, which also have a biotech part, which require fine precision instrumentation. The 5 decimal balance is the low range version for common use.

 

OK, so that is way the coin is sligtly 0.1mm larger than normal. No pressure was exerted from the side in this case.

 

It appears that you may have a good coin here . I had a US cent that was only struck on one side and sold it on Ebay a couple years ago. the buyer got it cheap and was very happy with it.

 

, and gratis. So, how would one determine whether the uniface was caused via double planchet by error or intentional by proof?

 

And some further interesting info. As I understood it, the lady who presented me with the gift inherited it as part of a collection from her grandfather who had a political position, which at that time was the opposition to the famous Pinochet regime in Chile. This particular 5 pesos and the 10 pesos were circulated commemorative coins celebrating the end of the regime. Therefore, the obvious reverse on the coin. The lady sold the rest of the coins years back to pay for her university fees. Unfortunately, this coin was chucked in a bucket with hundreds of other coins and left as is for years. It was only when she saw my son playing with a fake dollar that she brought the bunch of coins over. It was the only interesting one from hundreds. This is what makes coin collecting so interesting.

 

Nice, does the lab have a XRF spectroscope or a x-ray( or other) powder diffraction unit? they are used in metallurgy to give metal analysis. ( XRF is non-destructive ) and powder diffraction only takes a very minute amount. If so , you can check the face side verse the flat side , as if grinding or other altering occurred, the sides should show a little difference due to machining artifacts on the smooth side. I like precision equipment

 

No unfortunately not, we work most with mineral phases, using SEM, QEM SCAN and XRD. I did check with optical micrscope, and is my opinion that no griding took place. Only "damage" from being in the coin bin with others for years.