1923-S Standing Liberty Quarter Counterfeit
The first issue with this counterfeit example is the luster, it just looks “off” and the reason is the surface has graininess and is reflecting light in a non-natural manner. Authentic Standing Liberty Quarters don’t have a grainy appearance.
In hand the coin looks like a possible uncirculated coin, but blown up in these images and under magnification it is more apparent the coin is counterfeit.
Besides the graininess the coin is not struck well and the rim has lines that it shouldn’t, as well as the date digits are thicker than normal. It appears to have silver content in the alloy with a weight of 5.81g and a normal weight should be 6.3g.
It is not enough to silver test or weigh possible counterfeits, many are silver and many are common dates. So it’s best to know how US Coins are struck, look for die markers, or incorrect fonts on the letters and numbers.