Why Are There Diamonds on a Billiards Table?

When you see a billiards or pool table, you'll notice a series of small, colorful markers etched or inlaid on top of all four of the rails that surround the playing surface. These "diamonds" may seem to be there just for decoration, but they have some decidedly practical uses. Understanding what they are is basic to playing pool and billiard games.

  1. Description

    • Side rails with diamonds

      The diamonds (also called "sights") total 18 in number. They are equally spaced, six on each long side rail and three each on the head and end rails. "Diamonds" can be circles or really any shape that the table's owner fancies and is willing to pay for. Typically, they are no larger than a U.S. quarter coin.

    Materials

    • Diamond inlays on the most expensive tables are made from mother-of-pearl or abalone shell. Less expensive tables use imitations made of plastic or ordinary seashells or may just have colored shapes etched into the rail.

    Diamonds define the table grid

    • Connecting all the diamonds (counting the two side pockets where there would be diamonds) with imaginary straight lines creates a grid of 3 x 7 = 21 lines and intersecting points. These lines and intersections define the table's topography, dividing the table in half and each half into four squares and defining key points on the table's banks and the table top.

    Defining "behind the line"

    • Cue ball in the "kitchen" before the break

      The two-square area between the head rail and the imaginary line connecting the second set of side rail diamonds (counting from the head rail) is known as "behind the line" or "the kitchen" in billiard lingo. The white cue ball must be placed anywhere behind this line for the break and when taking penalty shots. A visible spot marks the center of this line, also called the "head string."

    Pinpointing "the spot"

    • Balls "spotted," ready for the break

      At the opposite or "foot rail" end of the table, at the intersection of a line drawn the length of the table connecting the middle diamonds on both end rails ("long string") and a line connecting the second set of side rail diamonds ("foot string") is the "foot spot," where balls are placed ("spotted") for the break or when "scratched." It is also visibly marked.

    Aiming points

    • Using an end rail diamond for a bank shot

      The diamonds are indispensable for expert pool and billiards players, who use them dynamically as aiming aids when making "bank" or "kick" shots off one or a combination of rails.