One of the balls, however, is slightly heavier or slightly lighter than the others, but you don’t know which ball or whether it is heavier or lighter. You do, however, have a balance scale.

Aramith 2-1/4" Regulation Size Billiard/Pool Ball: Super Pro Cup Cue Ball with 6 Red Dots Aramith 967 ratings ...

making billiard balls; difficulty in getting good ones and the cost. a simple but very skillful process--composition balls and the date of their perfection. share full article.

But mass markets in the western world for ivory billiard balls, combs, piano keys, and commercial trinklets, placed the wild elephant in serious jeopardy in the late 19th and early 20th centuries.