Why do some uncirculated coins have toning (tarnish, patina) and others, while still totally original (i.e. never dipped), do not? Why is the toning on some very dark while on others light enough for the sparkle of the coin’s lustre to clearly show through? Why are some coins toned in a single (monochromatic) color compared Read More
You and a collector friend are discussing a coin that each of you has just graded. Actually, the two of you are arguing because you disagree on the coin’s grade. Why the difference? Two possibilities follow. First, each of you are using a different frame of reference, i.e. a different set of grading standards. This Read More
Because of my grading activity at International Coin Certification Service I’m often asked “Do you really use a microscope to grade coins?” This is a regularly asked question because the stereo microscope is one of the first things people see when visiting the ICCS office. To exaggerate matters, I’m usually seen studying a coin with Read More