[From Dr. John Cammett via Jack Champaigne]
There are no quantitative standards or definitions that apply here and such are really unnecessary. How relatively big does a protuberance need to be to have it and its mate classified as a twin? Literal interpretation of the English word, twin, would require that the mates be of equal size. Otherwise the smaller would be called a protuberance. If one were to get really fancy, then a protuberance could be named thus only if it falls below the smallest size permitted in the size distribution. Otherwise it could be called a "twin". As I stated at the outset, there are no established schemes here and I see no necessity to establish any. It is simply that all such misshaped particles with rounded edges are lumped together as marginal and the lumped percentage is used to determine acceptability of the media sample.
Any elongated particle is marginal provided that the largest dimension falls within the size distribution and it has no angular features. Otherwise it would be deemed unnaceptable. It is not important to create special names or to judge particular shape.
