China 1888 French Piastre Silver Dollar Coin Sigma Tested #QT06

  
This coin has not been authenticated or graded by any professional grading service. Here is how I test each coin in the photos. Sigma Precious Metal Verifier Test. It checks the resistivity of the metals in the coin, I combine this with the specific gravity data (weight and dimensions) to determine what the coin is made out of. Certain other metals are less dense than silver, usually about 6% less dense which effects the weight so if the coins are usually all the same size, I can tell via the weight if something is off with the alloys within the coin because it will weigh less than normal. After a lot of experince, I can say the usual diameter is 39.8mm, not 39mm like most sites round the number down to, the center is usually 2.5mm and the rim is usually 2.7mm. If the dimensions and weight are as usual, I dont do a specific gravity equation. The coins are usually around 26.8 grams. I have seen a professional grading service be wrong in regards to certain coins being 26.4 grams and I have seen them grade heavier ones. I make sure it makes a sound to make sure there is not a tungsten core, but I do not rely on this test, I prefer specific gravity and the precious metal verifier to indicate the density of the metals and resistivity, for example copper is 6% less dense than silver so a silver plated copper coin with these dimensions, based on a specific gravity equation, would not weigh 26.8 grams typically, it would probably weigh 6% less i. A non silver coin would be below 26 grams. These coins were made in China so they are not going to sound exactly like an American silver dollar. If it was attracted to magnets, it would get pulled right onto that magnet. Note : Silver is DIAMAGNETIC (look up diamagnetism) so the coin will slightly wobble a little bit if you put it on your fingertip and put a strong magnet near it and bob the magnet up and down really close to it, this does not mean it is made of steel or is fake, or is attracted to magnets, it is the coin being very slightly repelled away from the magnetic field. Try it with a silver coin you already have. I put a very strong magnet 1mm away from every coin I test to show it is not magnetic and try to pick it up with the magnet. "But most Chinese coins are fake". Llook up Chinese Contemporary Counterfeits on Numista and the ones they show usually weigh below 26 grams or are magnetic or are the wrong size. I have caught at least 100 fake ones already as I have experience. Another thing, with the original sigma tester, if the line is in the left in the brackets, instead of the middle, that means more silver and if it is on the right in the brackets, that means less silver, it just depends on the province or period or coin. For it to test as silver, all it has to do is fall within the brackets on any given setting, so I usually use the. 9 setting, some coins tend to be higher, gansu coins having been slightly debased can be lower.