Marbles Dimensions
Marbles dimensions are not standardized, so manufacturers use 
different sizes. The ½ inch or 1.25 cm is one of the most common, although it is not the only one. Some of the bigger marbles are over 3 inches (7.75 cm). Some of the largest ones have a width exceeding 12 inches (30 cm).
Other Marbles Sizes
Even machine made marbles have different sizes. A close look will show that deviations of as much as +/- 1/16 inch diameter can be seen in some machine made marbles. The 12 mm diameter marbles are also popular sizes.
However, marbles dimensions advertised as 12 mm actually vary a bit, diameter wise. The marbles used for Chinese checkers measures 9/16". Many decorative marbles are made in this size as well.
For the target marble game, the 5/8" size is used, although other marbles may be used as well. The 16 mm is its equivalent size. In terms of comparison it is smaller than a dime.
The 3/4" marble is about the size of a penny. It isn’t that common though. The 7/8" marble size is not common either. The size is often used for art glass marbles rather than for games.
Other Marbles Dimensions
The 25 mm and 1" are just a tad larger than a quarter. The 35 mm is about 1 3/8" in diameter and the 42 mm is 1 5/8" in diameter.
Types of Marbles
There are many kinds of marbles. The alley or real marbles are constructed from alabaster or marble (alley stands for alabaster). These marbles have patterns or streaks. These are called by various names like butterfly, bumblebee, onyx, snake and corkscrew. The toothpaste has wavy streaks and are orange, white, red and black.
The turtle marbles have yellow and green streaks. The ade has opaque white strands. The oxblood has a patch that looks like blood. The oily marbles are opaque which have rainbow colors.
The pearls have pearl like color and the lutz has a swirling type. The onionskin is so-called due to its resemblance to onion skin. The clambroth has evenly spaced lines. The cat’s eye has a middle eye shaped core. The Devil’s eye has red and yellow color. The aggie is constructed from agate or other material similar to it.
Aside from the marbles dimensions, collectors also look at the style, age and condition of the marble. The materials used, the scarcity and its attractiveness are also important.
